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Biomedical subjects

T Wu

Publications and source records attributed to T Wu.

At least 127 records · Page 7Linked to original sources
PubMed1999

Evidence for mu opioid receptor on mouse spleen lymphocytes.

AIM: Using ohmefentanyl (Ohm), a high affinity mu opioid receptor agonist, to find whether mu opioid receptor exists on mouse spleen lymphocytes. METHODS: The proliferation rates of T-lymphocytes and B-lymphocytes were determined under various concentrations of Ohm with or without naloxone(Nal) in vitro. Binding characteristics of [3H] Ohm with mice spleen lymphocytes were studied by radioligand assays. RESULTS: Ohm 0.1 pmol.L(-1)-1 nmol.L-1 enhanced Con A-induced spleen T-cell proliferation in vitro. Nal 50 mumol.L-1, which per se enhanced the T-cell proliferation, blocked the enhancing effects of Ohm. However, Ohm had no effect on B-cell proliferation. Furthermore, a satisfactory saturable, specific, and reversible binding was demonstrated with Kd of (6.9 +/- 0.6) nmol.L-1, Bmax of (74 +/- 6) fmol/10(7) cells. The binding of [3H] Ohm was blocked by unlabeled Ohm or Nal. CONCLUSION: Stimulating effects of Ohm on lymphocytes were mediated by opioid receptors. Mouse spleen lymphocytes present mu opioid receptors.

Animals↗
PubMed1999

A brief history of antibiotic science.

As the greatest achievement in the history of microbiology, the story of antibiotic is an extremely inspired chapter in its history. Like the developmental process of other sciences, antibiotic reveals a history of first accumulating experience, followed by the stage of interpretation of the phenomena as other experimental study. Meantime, there is no end to the discovery of new antibiotics. Currently, the scope and province of antibiotic research is expanding both in its profundity and coverage.

Anti-Bacterial Agents↗
PubMed1999

[Development of the diagnosis and treatment of glaucoma in China].

Diagnosis and treatment of glaucoma is one of the greatest achievements in the development ophthalmology. The process of achieving is also a very inspiring chapter in its history. As histories of other sciences, the development of diagnosis and treatment of glaucoma is achieved through the following process: After accumulation for many years, then it entered the stage of explaining the phenomenon with the development of other sciences. Finally, its situation is determined by experiment and being widely applied in clinical practice. Meanwhile, there is no end for the findings of new diagnostic and therapeutic methods. More achievements will surely be made for developments in relevant sciences and increasing needs in clinical practice.

China↗
PubMed1999

[Effects of myocardial ischemia reperfusion injury on L-arginine/nitric oxide system in rat heart].

Ischemia reperfusion injury (IRI) model of rat heart was prepared by preperfusion for 15 min, then a suspension for 45 min and recycling reperfusion for 15 min with 30 ml KH buffer. The leakage of lactate dehydrogenase(LDH),protein, myoglobin and nitrite (NO2-) in the circular perfusion fluid were measured. Myocardial nitric oxide synthase(NOS) activity and L-arginine transport were observed. In the IR group, the leakage of LDH,protein, myoglobin and NO2- were increased respectively by 4.1,5.4,1 and 1.2 times(P<0.01) and NOS(tNOS, iNOS, cNOS) activity by 48.2%,43.2% and 52.1%,(P<0.01,respectively) as compared with the control group. L-arginine transport might be mediated by either high- or low-affinity transport system in cardiac tissue. In the IR group, L-arginine transport increased significantly with the V(max) being increased by 48% and 2 times respectively for the low-affinity and the high-affinity transport as compared with control. Michaelis constant (km) was decreased by 47.4% for low-affinity transport (P<0.05),but not significantly changed for the high-affinity transport. These results suggest that the increase of nitric oxide generation might result from the increased myocardial NOS activity and L-arginine transport during IRI.

Animals↗
PubMed1999

[Skeletal effect of xianzhen gubao on preventing prednisone-induced osteoporosis in male rats].

OBJECTIVE: To study the effect of Chinese medicine Xianzhengubao (XZGB) capsules of compound prescription on corticosteroid-induced osteoporosis in rats. METHOD: 3-month-old SD male rats were randomly divided into basal control and aging control, prednisone (4.5 mg.kg-1, ig, twice a week) and XZGB capsules were used in three different doses (0.2, 0.4, 0.8 g.kg-1.d-1 ig)6 times a week. All the rats were killed. On the 90th day afteradministration. The proximal tibiae were processed in undecalcified sections at a thickness of 4-10 microns for histomorphometric analysis. RESULT: Compared with the aging controls corticosteroid reduced markedly the trabecular bone mass due to increase of bone resorption and decrease of bone formation (%Tb. Ar 52.9%). Treatment with XZGB capsules in high doses increased significantly the trabecular area as compared with the hormone control(% Tb. Ar + 91.2%). The protective mechanism of XZGB capsules mainly consists in suppressing bone resorption and mildly increasing bone formation in rats. CONCLUSION: Xianzhen gubao capsules have an effect on preventing bone loss in rats induced by corticosteroid, and higher doses produce greater effect.

Animals↗
PubMed1999

Effects of ginsenosides on myocardial reperfusion arrhythmia and lipid superoxidation in high cholesterol diet rats.

To explore the effects of GSL on myocardial reperfusion arrhythmia and lipid superoxidation in high cholesterol diet rats. Hyperlipidemia model was set up with administered high cholesterol emulsion 15 ml/kg to rats orally for 14 days. In GSL group, rats were given GSL i.p. 75 mg/kg simultaneously when administered high cholesterol emulsion. The experiment of myocardial ischemia reperfusion was performed on all rats. The results showed: (1) After administration of high cholesterol emulsion to rats orally for 14 days, hyperlipidemia model was set up successfully, simultaneously treatment with GSL. It lowered serum lipid; (2) In hyperlipidemia state, serum MDA increased (p < 0.01, SOD and NO decreased markedly (p < 0.01 and p < 0.05 respectively) after 2 h of myocardial reperfusion; the rate of reperfusion arrhythmia (RPAr) increased within 10 min of reperfusion, four out of nine rats died of ventricular fibrillation (VF); and (3) GSL decreased MDA, increased SOD and NO after 2 h of myocardial reperfusion. All changes were significant (p < 0.01); the rate of RPAr decreased, no VF occurred and all rats survived. Hyperlipidemia aggravated myocardial ischemia reperfusion injury and increased the incidence of RPAr. The results suggested that GSL reduced myocardial ischemia reperfusion injury and RPAr in high cholesterol diet state through antiperoxidating and inducing the production of NO.

Animals↗
PubMed1999

[Diagnosis and surgical treatment of meningoencephalocele].

OBJECTIVE: To explore the characteristics of symptoms of meningoencephalocele and the selection of the most appropriate surgical approach. METHODS: From January 1986 to August 1997, 11 cases (frontoethmoidal type 5, basal 5, occipital 1) were retrospectively analyzed. RESULTS: Combined intraextracranial approach was applied 11 times and successful in 10 times; simple frontal approach 1 time, unsuccessful, lateral nasal incision 2 times, failed in 1. No recurrence was found in all successful operations during follow-up. CONCLUSION: Combined intra-extracranial approach, which provides excellent exposure and convenient repairing of skull base deficit is an ideal operation for meningoencephalocele.

Adolescent↗
PubMed1998

Sequence motifs in adenoviral DNA block immune activation by stimulatory CpG motifs.

Unmethylated CpG dinucleotides in particular base contexts (CpG-S motifs) are relatively common in bacterial DNA but are rare in vertebrate DNA. B cells and monocytes have the ability to detect such CpG-S motifs that trigger innate immune defenses with production of Th1-like cytokines. Despite comparable levels of unmethylated CpG dinucleotides, DNA from serotype 12 adenovirus is immune-stimulatory, but serotype 2 is nonstimulatory and can even inhibit activation by bacterial DNA. In type 12 genomes, the distribution of CpG-flanking bases is similar to that predicted by chance. However, in type 2 adenoviral DNA the immune stimulatory CpG-S motifs are outnumbered by a 15- to 30-fold excess of CpG dinucleotides in clusters of direct repeats or with a C on the 5' side or a G on the 3' side. Synthetic oligodeoxynucleotides containing these putative neutralizing (CpG-N) motifs block immune activation by CpG-S motifs in vitro and in vivo. Eliminating 52 of the 134 CpG-N motifs present in a DNA vaccine markedly enhanced its Th1-like function in vivo, which was increased further by the addition of CpG-S motifs. Thus, depending on the CpG motif, prokaryotic DNA can be either immune-stimulatory or neutralizing. These results have important implications for understanding microbial pathogenesis and molecular evolution and for the clinical development of DNA vaccines and gene therapy vectors.

Adenoviridae↗
PubMed1998

Maternal cigarette smoking, regular use of multivitamin/mineral supplements, and risk of fetal death: the 1988 National Maternal and Infant Health Survey.

Data from the 1988 National Maternal and Infant Health Survey were used to examine whether regular use of multivitamin/mineral supplements could modify the relation between maternal smoking and fetal death. Maternal smoking was defined as the self-reported average number of cigarettes smoked after recognition of pregnancy. Regular supplement use was defined as use of multivitamin/mineral supplements for at least 3 days per week during the 3 months before and/or after recognition of pregnancy. The sample comprises 12,465 singleton pregnancies, including 9,402 livebirths and 3,063 fetal deaths. Odds ratios were derived from logistic regression analyses after adjustment for a number of demographic and reproductive variables. Major findings are that 1) smoking increased the risk of fetal death; 2) regular supplement use either before or after recognition of pregnancy did not affect the risk of fetal death in the absence of maternal smoking; 3) odds ratios for fetal death among smoking women who regularly used supplements were generally smaller than those for women who did not regularly use supplements but who smoked a comparable number of cigarettes; and 4) a significant negative excess risk due to interaction was observed among women who regularly used supplements before recognition of pregnancy and smoked 20 or more cigarettes a day. These findings suggested that regular multivitamin/mineral supplement use might reduce the risk of fetal death associated with maternal smoking.

Adult↗
PubMed1998

Murine bone marrow expressing the neomycin resistance gene has no competitive disadvantage assessed in vivo.

The neomycin phosphotransferase (neo) gene is one of the most common marker genes used in gene transfer experimentation, but potential effects of neo gene expression in vivo have not been systematically investigated. Several early clinical retroviral gene transfer studies have suggested that neo gene expression could have deleterious effects on hematopoiesis, owing to a discrepancy between the level of neo-marked transduced marrow progenitor cells compared with mature circulating progeny cells posttransplantation (Brenner et al., 1993; Kohn et al., 1995; Brenner, 1996b). We examined the long-term in vivo repopulating ability of bone marrow from transgenic mice expressing neo from a strong constitutive promoter using a competitive repopulation assay. Different ratios of neo transgenic and wild-type congenic marrow cells were cotransplanted into W/Wv recipient mice. The percentages of blood cells containing the neo transgene in each group of recipient mice monitored for 4 months posttransplantation closely matched the input ratios of neo transgenic to congenic control marrow cells. Similar concordances of engraftment with input ratios of neo transgenic cells were also found in spleen, thymus, and whole marrow of recipient mice at 4 months posttransplantation. Analysis of the beta-hemoglobin phenotype (beta(single) for the neo transgenic and C57 control cells and beta(diffuse) for the congenic competitor HW80 cells) in recipients confirmed erythroid repopulation from neo transgenic marrow cells at levels matching the input ratios. We conclude that hematopoietic cells expressing neo had no engraftment or maturation defects detectable in vivo. These results suggest that the low-level contribution of vector-marked cells to circulating populations in clinical trials is not due to direct deleterious effects of neo gene expression on hematopoiesis.

Animals↗
PubMed1998

Application of ion chromatography to the semiconductor industry. I. Measurement of acidic airborne contaminants in cleanrooms.

The purpose of this study is to establish an analytical method for the simultaneous measurement of various acidic airborne contaminants in class 1 cleanrooms of a semiconductor fabrication facility (Fab). Acidic contaminants in air samples were adsorbed on silica gel tubes, extracted with carbonate-hydrogencarbonate solutions, and analyzed by ion chromatography. The recovery of HF was 100% and that of HCl was 91 approximately 100%. The method shows high resolution and sensitivity, and is capable for air analysis in the class 1 cleanroom. Different locations inside the cleanroom show deviations in the contaminant levels, indicating that the air quality is not the same throughout the cleanroom. The wet chemical station shows higher levels of contaminant concentrations than the other two areas. Each location also shows day-to-day variation.

Acids↗
PubMed1998

Hyperbaric oxygen and basic fibroblast growth factor promote growth of irradiated bone.

PURPOSE: The goal of the current experiment is to test for protective effect of hyperbaric oxygen (HBO) and basic fibroblast growth factor (bFGF) on bone growth. METHODS AND MATERIALS: Control C3H mice received hind leg irradiation at 0, 10, 20, or 30 Gy. HBO-treated groups received radiation 1, 5, or 9 weeks before beginning HBO. The remaining groups began bFGF +/- HBO 1 or 5 weeks after 30 Gy. HBO treatments were given 5 days per week for 4 weeks at 2 ATA for 3 h/day. bFGF was given intravenously at 6 microg twice a week for 4 weeks. RESULTS: HBO improved bone growth after radiation in the 10 and 20 Gy groups. At 18 weeks control tibia length discrepancy is 0.0, 4.2, 8.2, and 10.7% after 0, 10, 20, and 30 Gy, respectively. HBO beginning in week 1, 5, or 9 following 10 Gy decreased these discrepancies to 2.0% (p < 0.05), 1.8% (p < 0.05), and 2.4% (p < 0.05), respectively. After 20 Gy, HBO decreased these discrepancies to 7.0% (p = ns), 4.9% (p < 0.05), and 3.6% (p < 0.05), respectively. At 30 Gy, HBO alone had no effect on bone shortening. bFGF improved tibia length discrepancy with or without HBO. At 18 weeks length discrepancies were 6.5% (p < 0.05) and 7.3 (p < 0.05), and after bFGF alone were 6.8% (p < 0.05) and 7.3% (p < 0.05) for treatment beginning in week 1 or 5, respectively. Tibial growth at 18 and 33 weeks following radiation were similar. CONCLUSION: Radiation effects on bone growth can be significant reduced by HBO after 10 or 20 Gy, but not after 30 Gy. At 30 Gy bFGF still significantly reduced the degree of bone shortening, but HBO provided no added benefit to bFGF therapy.

Animals↗
PubMed1998

Study on amino acid composition of HSP70 and the level of plasma free amino acids of workers with long-term exposure to harmful factors.

In order to know the practical value of heat stress protein 70 (HSP70) and to know the changes of plasma free amino acids of workers with the induction of HSP70 by harmful factors, the amino acid composition of major HSP, HSP70 purified from the heated cultured human leukemia cancer cell line K562, rabbit liver, rat liver and heart, and mouse liver with two-step procedures of DE52-cellulose ion exchange chromatography and affinity chromatography on ATP-agarose was examined. The level of plasma free amino acids of workers with long-term exposure to heat, carbon monoxide and the combined effect of both heat and carbon monoxide was also investigated. The results showed that the three richest amino acids in HSP70 of all origins were Gly, Glu and Asp, except that of rat heart which was rich in Gly, Phe and Glu. Additionally, Lys, Val, Leu and Ala were also found very rich in HSP70 of all origins. Compared with controls, the most of plasma free amino acids tended to increase and free methionine and tryptophan were increased significantly (P < 0.05) after a long-term exposure to heat, carbon monoxide, and both. These findings suggested that further studies need to be done to find the substances or drugs which induce the synthesis of HSP70 and reduce the inhibition of synthesis of normal proteins for the purpose of protecting people with exposure to harmful factors against the damage of the factors.

Amino Acids↗
PubMed1998

Can regular multivitamin/mineral supplementation modify the relation between maternal smoking and select adverse birth outcomes?

PURPOSE: The purpose of this study was to examine whether or not regular multivitamin/mineral supplementation can modify the relation between maternal smoking and preterm birth (gestational age < 37 weeks), very-low-birthweight (VLBW) (< 1500 g), moderately-low-birthweight (MLBW) (< 2499 g), or small-for-gestational-age (SGA) (< 10th percentile of birth weight for gestational age). METHODS: Live birth data from the 1988 National Maternal and Infant Health Survey (NMIHS) were used for the analysis. Maternal smoking referred to self-reported average number of cigarettes smoked after recognition of pregnancy, while regular multivitamin/mineral supplementation referred to use of multivitamin/mineral supplements for at least three days per week during the three months before and/or after recognition of pregnancy. Sample sizes included 9402 singleton infants for the analysis of preterm birth, 9395 for very or moderately low birthweight, and 9363 for small-for-gestational-age. Odds ratios were derived from logistic regression analyses after adjusting for a number of demographic and reproductive variables. RESULTS: Major results include: 1) increased risks for the adverse outcomes studied were observed among smoking women; 2) no effect of regular multivitamin/mineral supplementation in the absence of maternal smoking was revealed; and 3) relative excess risks due to interaction at different smoking levels and overall interactions between smoking and supplementation were not observed. CONCLUSIONS: These results suggest that regular multivitamin/mineral supplementation does not minimize the adverse effects associated with maternal smoking.

Adult↗
PubMed1998

Actinomycin D inhibits human immunodeficiency virus type 1 minus-strand transfer in in vitro and endogenous reverse transcriptase assays.

In this report we demonstrate that human immunodeficiency virus type 1 (HIV-1) minus-strand transfer, assayed in vitro and in endogenous reactions, is greatly inhibited by actinomycin D. Previously we showed that HIV-1 nucleocapsid (NC) protein (a nucleic acid chaperone catalyzing nucleic acid rearrangements which lead to more thermodynamically stable conformations) dramatically stimulates HIV-1 minus-strand transfer by preventing TAR-dependent self-priming from minus-strand strong-stop DNA [(-) SSDNA]. Despite this potent activity, the addition of NC to in vitro reactions with actinomycin D results in only a modest increase in the 50% inhibitory concentration (IC50) for the drug. PCR analysis of HIV-1 endogenous reactions indicates that minus-strand transfer is inhibited by the drug with an IC50 similar to that observed when NC is present in the in vitro system. Taken together, these results demonstrate that NC cannot overcome the inhibitory effect of actinomycin D on minus-strand transfer. Other experiments reveal that at actinomycin D concentrations which severely curtail minus-strand transfer, neither the synthesis of (-) SSDNA nor RNase H degradation of donor RNA is affected; however, the annealing of (-) SSDNA to acceptor RNA is significantly reduced. Thus, inhibition of the annealing reaction is responsible for actinomycin D-mediated inhibition of strand transfer. Since NC (but not reverse transcriptase) is required for efficient annealing, we conclude that actinomycin D inhibits minus-strand transfer by blocking the nucleic acid chaperone activity of NC. Our findings also suggest that actinomycin D, already approved for treatment of certain tumors, might be useful in combination therapy for AIDS.

Anti-HIV Agents↗
PubMed1998

MR-guided focused-ultrasound ablation system: determination of precision and accuracy in preparation for clinical trials.

The authors analyzed the accuracy and precision of focal-spot placement with a magnetic resonance-guided, focused-ultrasound system. Average absolute accuracy errors ranged from 0.2 to 1.0 mm, and average absolute individual precision errors ranged from 0.2 to 0.3 mm. To prevent damage to vital structures, single sonications and sonication grids should be placed beyond approximately 2 and 1 mm, respectively.

Magnetic Resonance Imaging↗
PubMed1998

Low molecular weight heparin reduces triglyceride, VLDL and cholesterol/HDL levels in hyperlipidemic diabetic patients on hemodialysis.

BACKGROUND: Low molecular weight heparin (LMWH) provides a safe and effective alternative for hemodialysis anticoagulation. While unfractionated (UF) heparin has been implicated in hyperlipidemia, the effect of LMWH on the lipid profile in nondiabetic patients is controversial in chronic hemodialysis. The effect of LMWH in diabetic patients, a high risk group of hyperlipidemia, has not been studied. METHOD: LMWH was tested for its safety and efficacy in 10 nondiabetic Taiwanese patients. To evaluate influence of lipid profile, a crossover study was carried out in 10 type II diabetic patients with poor blood sugar control associated with high triglyceride (430.4 +/- 101.1 mg/dl) and total cholesterol levels (219.2 +/- 12.7 mg/dl) using UF heparin for more than 1 year. These patients were subjected to Fraxiparine, an LMWH, for 6 months and then switched back to UF heparin for another 6 months. Lipid profiles were measured every 2 months without prescribing lipid-lowering agents and the blood sugar was maintained at stationary levels. RESULTS: LMWH is safe and effective in Taiwanese patients as a single bolus injection and maintains a 9.4% higher platelet count immediate postdialysis compared to UF heparin. With high HbA1c levels (9.6 +/- 0.6%), mean triglyceride and VLDL levels started to decrease at the 4th month after LMWH treatment and reached a 34% reduction in triglyceride, a 26.2% reduction in VLDL, and a 19% reduction of total cholesterol/HDL ratio at the 6th month. Increments of triglyceride levels were found at the 6th month after a switch back to UF heparin. The levels of total cholesterol, LDL-cholesterol, HDL-cholesterol, apolipoprotein A-1 and B remained unchanged. CONCLUSION: LMWH may be beneficial to lipid control in hyperlipidemic diabetic patients on hemodialysis.

Adult↗