PubMed Health⌕ Search

Biomedical subjects

Y C Su

Publications and source records attributed to Y C Su.

67 records · Page 4Linked to original sources
PubMed1992

A biocompatible needle-type glucose sensor based on platinum-electroplated carbon electrode.

A biocompatible needle-type glucose sensor with a 3-electrode configuration was constructed. A platinum-electroplated carbon stick was used as the working electrode, Ag/AgCl as the reference electrode, and a disposable hypodermic needle made of stainless steel as the counter electrode. A Nafion membrane, an immobilized glucose oxidase (GOD) membrane, and a biocompatible membrane with diffusion-limiting effect were coated successively onto the working electrode. The sensor showed a rapid response (< 120 s in batch operation), good reproducibility (RE < 3%), good stability (over 36 h in control serum), a wide dynamic range (5-600 mg/dL glucose), and superior biocompatibility. It was used to determine glucose in serum. The data obtained from the sensor showed good agreement with that from a clinical autoanalyzer (R > 0.95).

Biocompatible Materials↗
PubMed1992

Use of an oligonucleotide probe to detect Vibrio parahaemolyticus in artificially contaminated oysters.

A 26-mer oligonucleotide specific to Vibrio parahaemolyticus was synthesized from a 1,275-bp thermostable direct hemolysin (tdh) gene. This oligonucleotide probe specifically reacted with DNA from 89 of 95 V. parahaemolyticus isolates but not with DNA from other vibrios or other enteric and nonenteric organisms (n = 48). The probe hybridized with Southern blots of 0.5-kb HindIII-restricted chromosomal DNA fragments from all but five V. parahaemolyticus test isolates. The probe could be used to directly identify V. parahaemolyticus in artificially contaminated food without an isolation step.

Animals↗
PubMed1991

Effects of cigarette smoking, hypoxia and vasoactive mediators on the production of PGI2 and TXA2 in cultured pulmonary artery endothelial cells.

Effects of cigarette smoke extract (CSE) and some vasoactive mediators on the production of PGI2 and TXA2 in normoxic and hypoxic pulmonary artery endothelial cells (PAECs) in culture were studied. The production of PGI2 in PAECs was inhibited by hypoxia or verapamil, but promoted by angiotensin II (A II), noradrenaline (NE) or platelet activating factor (PAF), while that of TXA2 slightly increased except when treated with PAF. The effect of AII, NE, PAF and verapamil, however, was not influenced by hypoxia. CSE inhibited the production of PGI2 in normoxic PAECs but did not further reduce 6-keto-PGF1 alpha in hypoxic PAECs medium. The results suggest that a) the production of PGI2 during hypoxia might be stimulated by vasoactive mediators produced during hypoxia, not by hypoxia directly; b) the production and release of PGI2 were related to intracellular calcium; c) the augmented production of PGI2 might be one of the mechanisms in the pulmonary vasodilating role of PAF; and d) prostaglandin production might be associated with the alteration of hypoxic pulmonary vasoreactivity after cigarette smoking.

6-Ketoprostaglandin F1 alpha↗
PubMed1991

Production of beta-fructofuranosidase with transfructosylating activity for fructooligosaccharides synthesis by Aspergillus japonicus NTU-1249.

Microbial beta-fructofuranosidases with transfructosylating activity can catalyze the transfructosylation of sucrose and synthesize fructooligosaccharides. Aspergillus japonicus NTU-1249 isolated from natural habitat was found to produce a significant amount of beta-fructofuranosidase with high transfructosylating activity and to have the potential for industrial production of fructooligosaccharides. In order to improve it's enzyme productivity, the medium composition and the cultivation conditions for A. japonicus NTU-1249 were studied. A. japonicus NTU-1249 can produce 83.5 units of transfructosylating activity per ml broth when cultivated in a shaking flask at 28 degrees C for 72 hours with a modified medium containing 80 g/l sucrose, 15 g/l soybean flour, 5 g/l yeast extract and 5 g/l NaCl at an initial pH of 6.0. The enzyme productivity was also optimized by submerged cultivation in a 5-litre jar fermentor with aeration at 1.5 vvm and agitation at 500 rpm. Under these operating conditions, the productivity of transfructosylating activity increased to 185.6 U/ml. Furthermore, the transfructosylating activity was improved to 256.1 U/ml in 1,000-litre pilot-scale fermentor. Enzymatic synthesis of fructooligosaccharides by beta-fructofuranosidase from A. japonicus NTU-1249 was performed in batch type by adding 5.6 units of transfructosylating activity per gram of sucrose to a 50% (w/v) sucrose solution at pH 5.0 and 50 degrees C. The yield of fructooligosaccharides was about 60% after reaction for 24 hours, and the syrup produced contained 29.8% (w/v) fructooligosaccharides, 15.2% (w/v) glucose and 5.0% (w/v) sucrose.

Aspergillus↗
PubMed1990

Strain difference in pulmonary vascular responsiveness to hypoxia in rats.

The difference in pulmonary vascular response to hypoxia between Hilltop Sprague-Dawley (HT) rats and Wistar (W) rats was studied. Effects of inhibitor of leukotriene (LT) synthesis or prostaglandin (PG) synthesis on hypoxic pulmonary vasoconstriction (HPV) and chronic pulmonary hypertension were observed, and variations in plasma TXB2 and 6-keto-PGF1 alpha during hypoxia were determined. The results showed that in rats of both strains LTs are the major mediator of HPV, which is also mediated by vasoconstrictive PGs in HT rats, while modulated by vasodilative PGs in W rats. This might be the crucial mechanism responsible for the higher pulmonary vascular responsiveness in HT rats. Differences in the modulating effect of histamine and in the structural feature of pulmonary arteriole might be contributing factors as well.

Animals↗
PubMed1990

[Lysine production by Brevibacterium divaricatum NTU-2 and its recovery from the fermentation broth].

An accumulation of L-lysine of about 42 g/l (as L-lysine-HCl) was obtained by cultivating Brevibacterium divaricatum NTU-2 in a medium containing 10.0% glucose, 4.0% (NH4)2 SO4, 0.1% KH2 PO4, 0.04% Mg SO4.7H2 O, 30 ml/l soybean meal hydrolysate, 50 mg/l DL-methionine, 100 micrograms/l d-biotin, 100 micrograms/l thiamine-HCl and 5% CaCO3 at pH 7.0. The yield was about 48.8% based on consumed glucose. The L-lysine accumulated in the broth was recovered and purified by simply using a strong cation-exchange resin, Diaion SK1B. The absorbed L-lysine was eluted with 4% ammonia water, and the average adsorption and desorption rates estimated (by 10 repeated experiments) were found to be 96.1% and 97.5%, respectively. The eluate was concentrated to about 50% by volume and adjusted to pH 4.0 with 8 N HCl. The solution was concentrated again to one half volume and followed by adding three volumes of 95% ethanol. The crude crystals of L-lysine-HCl in purity of 89.5% were obtained by filtration. The recovery was 93.5%. The resulting crude crystals were then dissolved in water, and subjected to decolorization with 0.5% active carbon. The decolorized solution thus obtained was recrystalized by concentration and 95% ethanol addition. After filtration and drying at 80 degrees C for 3 hr, white crystalline L-lysine with purity of 99.2% was finally obtained. The overall recovery of L-lysine was up to 86.7%.

Brevibacterium↗
PubMed1989

Relation of TXA2 and PGI2 to the difference in hypoxic pulmonary vasoconstriction between different strains of rats.

TXB2 and 6-keto-PGF1 alpha levels in arterial and venous plasma of Wistar and Hilltop rats during hypoxia were measured to investigate the roles of TXA2 and PGI2 in hypoxic pulmonary vasoconstriction (HPV) and responsiveness difference of pulmonary vessels to hypoxia between different strains of rats. The results showed that PGI2 might play an important role in maintaining the low resistance in pulmonary circulation of these two strains of rats. Increased TXA2 during hypoxia may partially mediate HPV in Wistar rats, while augmented PGI2 during hypoxia may modulate HPV in Wistar rats. This might be the important mechanism responsible for more intensive responsiveness of pulmonary vessels to hypoxia in Hilltop rats than in Wistar rats.

6-Ketoprostaglandin F1 alpha↗
PubMed1986

A new biosensor for rapid BOD estimation by using immobilized growing cell beads.

A closed, reactor-type sensor system for rapid estimation of BOD by the use of immobilized growing whole cells of a facultative bacterium, Bacillus polymyxa D-21, in kappa-carrageenan and an oxygen electrode is described. This system consists of a transformer, a recorder, a thermostated water bath (30 +/- 1 degree C), a magnetic stirrer (200 rpm), an oxygen electrode, and a flask containing 10 g (wet weight) immobilized cell beads of 2-3 mm in diameter. The total time required for an assay is less than 15 min. The calibration curves obtained show a linear relationship between the rate of oxygen consumption and the concentration of standard wastewater solution which contains equal amounts of glucose and L-glutamic acid each at a concentration below 10 mg/l. The measurement is independent of the pH of the wastewater solution under investigation. The rate of oxygen consumption was reproducible with an average relative error of 5.89% when a standard wastewater solution containing 12 mg/l of glucose and 12 mg/l of L-glutamic acid was assayed 54 times. When the immobilized cell beads were suspended in a 0.1 M phosphate buffer (pH 6.0) and stored at 25 degrees C, the response of the sensor system remained unchanged for about 30 days. However, based on the observed linear relationship between the rate of oxygen consumption and the concentration of standard wastewater solution, the sensor system should remain usable for at least 2 months. There is a good correlation between BOD5 determined by a conventional method and BOD5 determined by the proposed method when wastewater samples from a local fermentation factory were assayed.

Bacillus↗
PubMed1984

The microbial production of amylase inhibitor and its application. I. Isolation and cultivation of Streptomyces nigrifaciens NTU-3314.

In the course of screening amylase inhibitor producing, microorganisms, a strain identified as Streptomyces nigrifaciens NTU-3314 was found to have the highest inhibitor-producing ability among the other isolated strains. This strain was aerobically cultured at 30 degrees C in a 5l jar fermentor with a working volume of 2l. The optimum cultural medium consisted of defatted soybean flake 3.0%, potato starch 4.0%, casein 0.6%, sucrose 0.6%, serine 0.02% and NaCl 0.8% (pH 7.0). With an aeration rate of 1.5 vvm, an agitation speed of 300 rpm and an inoculum of 15% seed (previously grown in seed medium 3), the highest amount of inhibitor was obtained after 24 hours of cultivation. The amylase inhibitor produced had inhibitory effects on both alpha-amylase and glucoamylase, but not on beta-amylase, alpha-glucosidase, beta-glucosidase or dextranase. It was quite stable in 0.1M phosphate buffer (pH 7.0) and nearly 100% of its activity was retained even after boiling at 100 degrees C for 20 min.

Amylases↗
PubMedDate not supplied

Sulphite analysis of food ingredients: false positive responses with butter flavourings in the optimized Monier-Williams method.

The analysis of commercial butter flavouring materials for sulphite by the optimized Monier-Williams method revealed detectable levels of apparent sulphur dioxide (1810 ppm for butter oil, 5760 ppm for butter flavour, and 14.5 ppm for butter derivative) even though the manufacturers claimed that no sulphites were used in processing these ingredients. The presence of volatile fatty acids in these ingredients may explain the anomalous results. Volatile fatty acids were found to interfere with the optimized Monier-Williams method for sulphite determination, detectable levels of titratable acid being found in the hydrogen peroxide trap with amounts of volatile fatty acids as low as 0.3 g. The levels of volatile fatty acids in foods would not be predicted to cause significant interference in the analysis of sulphite residues by the optimized Monier-Williams method. However, this analytical procedure is not recommended for the analysis of sulphite residues in food ingredients containing substantial amounts of volatile fatty acids. Alternative methods for the detection of residual sulphite, such as the sulphite oxidase assay and the colorimetric para-rosaniline method, are not subject to interference by volatile fatty acids.

Butter↗
PubMedDate not supplied

Evaluation of an office-based urine test for detecting Helicobacter pylori: a Prospective Pilot Study.

BACKGROUND/AIMS: To ascertain the reliability of a newly developed office-based urine test, the RAPIRUN test, used for detection of H. pylori infection. METHODOLOGY: Urine specimens from 142 consecutive patients undergoing gastroendoscopy (77 men, 65 women; mean 52.0 years) were tested with RAPIRUN at the same time. The total reaction time for the urine test is 20 min. None of the patients had received any H. pylori eradicating treatment. The H. pylori status was evaluated based on 5 different tests: culture, histology, biopsy urease test, 13C-urea breath test, and the RAPIRUN test. A commercial office-based kit using an immunochromatographic technique was used to examine urine samples for H. pylori antibody. H. pylori status was defined as positive when the culture was positive or if 2 of the other 3 tests (histology, biopsy urease test, and 13C-urea breath test were positive. RESULTS: Of 93 patients with H. pylori infection, 88 were tested as positive by RAPIRUN (sensitivity 94.6%). Of 48 patients without infection, 43 were found to be negative by RAPIRUN (specificity 89.6%). One case with an invalid urine test was excluded. CONCLUSIONS: This urine test is a rapid, inexpensive, reliable and easy-to-use tool for the diagnosis of H. pylori infection in untreated patients. It can be used for mass screening of patients' H. pylori status, particularly in children, postgastrectomy patients, uncooperative patients, and patients undergoing bismuth or proton pump inhibitor treatment.

Adenocarcinoma↗
PubMedDate not supplied

Breast-feeding counseling by a 24-hour telephone hot-line.

A 24-hour telephone hot-line functioning as a counseling service and case registry was included in a multi-faceted breast-feeding promotion program. The mothers could speak directly to especially trained staff members in a municipal hospital. All the questions were answered according to an "Answering Book" which included the anticipated question and the optimum answer. A total of 201 calls, which included 340 problems, were recorded from January 1, 1993 to October 31, 1993. Almost all the calls were made by the mothers (99%), and more than half (57.7%) of the mothers were primiparous. Most of the calls (79.6%) were made between 8 AM to 4 PM. The questions were frequently raised when the baby was aged 8 to 14 days (23.4%). The most frequently asked questions were: (1) insufficient milk? (14.1%), (2) frequent and loose stools? (13.2%), (3) weaning? (10.3%), (4) drugs? (6.8%), (5) additional formula or water? (6.2%), and (6) maternal contraindication? (6.2%). Although the impact of this telephone consultation could not be properly evaluated, the incidence of breast-feeding during hospital stay increased from 50% to 73.4%, and breast-feeding for more than 1 month increased from 22.7% to 42.2% before and after the whole promotion program. It is recommended that health care professionals provide more help when the mother leaves the hospital. A nation-wide toll-free telephone operated by the Department of Health to increase the chance of successful breast-feeding is also recommended.

Breast Feeding↗