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Biomedical subjects

D Wu

Publications and source records attributed to D Wu.

At least 289 records · Page 16Linked to original sources
PubMed1998

Baroreflex-mediated bradycardia is blunted by intravenous mu- but not kappa-opioid agonists.

To assess the cardiovascular effects of systemically administered opioid agonists, changes in blood pressure and heart rate were observed after intravenous (i.v.) administration of U50,488H (trans-3,4-dichloro-N-[2-(1-pyrrolidinyl) cyclohexyl]benzeneacetamide), a selective kappa-opioid receptor agonist, and DAMGO (D-Ala2, N-Me-Phe4, Gly5-ol), a selective mu-opioid-receptor agonist. Intravenous administration of U50,488H (1.2 mg/kg) and DAMGO (0.3 mg/kg) to the awake sheep resulted in an immediate increase in blood pressure. The pressor response to U50,488H was accompanied by an increase in heart rate. In contrast, there was no accompanying change in heart rate in response to DAMGO. We hypothesized that the lack of a reflex bradycardia to the pressor responses of both the mu- and kappa-opioid-receptor agonists was due to a blunting of baroreflex-mediated bradycardia. The reflex bradycardia to norepinephrine (0.6 microg/kg/min) was significantly reduced in the presence of DAMGO but not U50,488H. In view of the lack of effect of U50,488H on the baroreflex, we further hypothesized that the tachycardia it elicited was due to an increase in sympathetic activity. Pretreatment with propranolol (0.1 mg/kg) completely blocked the tachycardia elicited by U50,488H. These data suggest that the lack of a reflex bradycardia to the pressor response of DAMGO is due to a blunting of baroreflex-mediated bradycardia. In contrast, the increase in heart rate caused by U50,488H is mediated by sympathetic activation of the heart.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1998

On the algorithm for computing body surface Laplacians in an inhomogeneous volume conductor of arbitrary shape.

In this short communication, a corrected version of algorithm for calculating the body surface Laplacian (BSL) in an inhomogeneous volume conductor of arbitrary shape is described. The present computer simulation results show that the corrected algorithm can give an accurate numerical solution. This algorithm was then applied to examine the effect of the lung inhomogeneity on the BSL's in a realistically shaped torso model. The simulation results show that the low-conductivity lungs have little effect on both topology and magnitudes of body surface Laplacian maps (BSLM's) for a single dipole source.

Algorithms↗
PubMed1998

CD4-Induced conformational changes in the human immunodeficiency virus type 1 gp120 glycoprotein: consequences for virus entry and neutralization.

Human immunodeficiency virus type 1 (HIV-1) entry into target cells involves sequential binding of the gp120 exterior envelope glycoprotein to CD4 and to specific chemokine receptors. Soluble CD4 (sCD4) is thought to mimic membrane-anchored CD4, and its binding alters the conformation of the HIV-1 envelope glycoproteins. Two cross-competing monoclonal antibodies, 17b and CG10, that recognize CD4-inducible gp120 epitopes and that block gp120-chemokine receptor binding were used to investigate the nature and functional significance of gp120 conformational changes initiated by CD4 binding. Envelope glycoproteins derived from both T-cell line-adapted and primary HIV-1 isolates exhibited increased binding of the 17b antibody in the presence of sCD4. CD4-induced exposure of the 17b epitope on the oligomeric envelope glycoprotein complex occurred over a wide range of temperatures and involved movement of the gp120 V1/V2 variable loops. Amino acid changes that reduced the efficiency of 17b epitope exposure following CD4 binding invariably compromised the ability of the HIV-1 envelope glycoproteins to form syncytia or to support virus entry. Comparison of the CD4 dependence and neutralization efficiencies of the 17b and CG10 antibodies suggested that the epitopes for these antibodies are minimally accessible following attachment of gp120 to cell surface CD4. These results underscore the functional importance of these CD4-induced changes in gp120 conformation and illustrate viral strategies for sequestering chemokine receptor-binding regions from the humoral immune response.

Animals↗
PubMed1998

Age-associated increase in PGE2 synthesis and COX activity in murine macrophages is reversed by vitamin E.

We previously showed that increased macrophage and PGE2 production with age is due to enhanced cyclooxygenase (COX) activity and COX-2 expression. This study determined the effect of vitamin E supplementation on macrophage PGE2 synthesis in young and old mice and its underlying mechanism. Mice were fed 30 or 500 parts per million vitamin E for 30 days. Lipopolysaccharide (LPS)-stimulated macrophages from old mice produced significantly more PGE2 than those from young mice. Vitamin E supplementation reversed the increased PGE2 production in old mice but had no effect on macrophage PGE2 production in young mice. In both LPS-stimulated and unstimulated macrophages, COX activity was significantly higher in old than in young mice at all intervals. Vitamin E supplementation completely reversed the increased COX activity in old mice to levels comparable to those of young mice but had no effect on macrophage COX activity of young mice or on COX-1 and COX-2 protein or COX-2 mRNA expression in young or old mice. Thus vitamin E reverses the age-associated increase in macrophage PGE2 production and COX activity. Vitamin E exerts its effect posttranslationally, by inhibiting COX activity.

Aging↗
PubMed1998

Video-assisted cardiac surgery: preliminary results in Chang Gung Memorial Hospital.

OBJECTIVE: To summarize the experience of utilization of video-assisted endoscopy in 91 patients operated on at Chang Gung Memorial Hospital, Taipei, China. METHODS: From October 1995, through August 1996, 91 patients (44 male and 47 female) received video-assisted cardiac surgery (VACS). Their ages ranged from 1 year to 79.5 years (25.7 +/- 21.7). Indications for surgery were atrial septal defect (59 patients), ventricular septal defect (15), coronary artery disease (4), severe mitral regurgitation (4), severe tricuspid regurgitation (3), thrombosis of mitral mechanical prosthesis (3), left atrial tumor (2), and left ventricular thrombus with dilated cardiomyopathy (1). The VACS was performed through right or left anterior minithoracotomy and guided by video-assisted endoscopic techniques by means of projected images on the video monitor under extracorporeal circulation. The aorta was not cross-clamped and the myocardium was protected by continuous coronary perfusion with hypothermic fibrillatory arrest (rectal temperature 22.6 +/- 4.0 degrees C). Conventional instruments were used. RESULTS: All lesions were corrected successfully. The bypass time was 27 to 335 minutes (72.8 +/- 52.7). The operative time was 1.3 to 8.5 hours (3.0 +/- 1.7). There were no operative deaths and 3 late deaths. Follow-up was complete in all survivors (6 to 16 months, mean 8.7). Most of them were found to be in NYHA functional I or II. CONCLUSION: Our preliminary experiences demonstrate that VACS is simple and effective in surgical correction of selected cardiac lesions. Short-term results show good outcomes.

Adolescent↗
PubMed1998

The test of motion perception of the normal Chinese subjects.

OBJECTIVE: To investigate the characteristic of motion perception (MP) of normal Chinese subjects. METHODS: MPs were recorded from 56 normal subjects (112 eyes), age ranged from 11 to 68 years, and the MP software was controlled by PC compatible computer which appeared as the vertical bar targets in VGA screen. RESULTS: The Mp rates were ascending gradually from 10 age-group to 30 age-group as the age increased in the 2 pixels (2P) horizontal motion, and the MP rates were decreasing gradually over 40 age-group, and the MP rates were not affected by the age in the 4 pixels (4P), 6 pixels (6P) horizontal motion and > 40 Hz flick motion. There was no relation between the MP and the sex and the different eyes. CONCLUSIONS: The characteristic of MP of the normal Chinese subjects was determined and the results provided the normal reference values.

Adolescent↗
PubMed1998

[Changes in blood levels of nitric oxide, oxidation and lipoperoxidation in patients with silicosis].

OBJECTIVE: To explore the relationship between nitric oxide, oxidation, lipoperoxidation and silicosis. METHODS: Blood plasma levels of nitric oxide (P-NO), vitamin C (P-VC), vitamin E (P-VE), beta-carotene (P-beta-CAR), lipoperoxidase (P-LPO), and erythrocyte activities of superoxide dismutase (E-SOD), catalase (E-CAT), glutathione peroxidase (E-GSH-Px) and lipoperoxidase (E-LPO) were measured in 73 patients with silicosis and 60 healthy subjects. RESULTS: The average levels of P-VC, P-VE, P-beta-CAR, E-SOD, E-CAT and E-GSH-Px were significantly lower and the average levels of P-NO, P-LPO and E-LPO significantly increased in the silicosis with varied severity of the disease and lung function status more than in the controls. There was linear relationship between all the above indices and length of the disease. Stepwise regression analysis showed that the severity of the disease and lung function status correlated most closely with the levels of P-NO, P-VE, E-SOD and E-LPO. CONCLUSION: Metabolism of nitric oxide was abnormal, balance between oxidation and antioxidation was disturbed seriously, and oxidation and lipoperoxidation reaction pathologically exacerbated in the bodies of the patient with silicosis.

Adult↗
PubMed1998

A comparative observation on treatment of heart failure due to diastolic insufficiency of the left ventricle--a report of 43 cases.

43 cases of heart failure due to diastolic insufficiency of the left ventricle were treated with TCM differential treatment as the treatment group, the total effective rate being 86.0%. Statistically significant difference (P < 0.05) in the therapeutic effects was found between the treatment group and control (25 cases) group. Improvement of the left ventricular diastole in the treatment group was more obvious than that of the control group (P < 0.01), while contractility of the left ventricle was also improved to a certain extent.

Adult↗
PubMed1998

[Infection of sexually transmitted diseases in female patients with inflammation of genitourinary tract by polymerase chain reaction].

Using polymerase chain reaction (PCR), Neisseria gonorrhoeae (NG) from 5899 female out-patients with inflammation of genitourinary tract was detected. Among 18.57% positive cases, the effective rates of the gonorrhea (26.07%) and urethritis (23.73%) were higher than those of the Condyloma acuminatum (CA) (17.73%), vaginitis (17.70%), and cervicitis (11.54%)(P< 0.01), indicating that there were various degrees of NG infection in genitourinary tract diseases. Moreover, Ureaplasma urealyticum (UU), Chlamydia trachomatis (CT), NG, and human papilloma viruses (HPV) were also detected in 8329 patients with vaginitis. Among 20.01% positive cases, the positive rate of UU was 39.95%, CT 21.36%, NG 17.70%, and HPV 16.40%. Variance analysis showed that significant differences existed in the vaginitis caused by different pathogens ( P <0.01); namely, four kinds of pathogens were present in the patients with vaginitis.

Adult↗
PubMed1998

[Effect of fluoride on proliferation and differentiation in rat and mouse embryo bud cell in vitro].

The effect of fluoride on differentiation and proliferation of rat and mouse embryo limb bud cell were studied with micromass cultures in vitro. Embryo limb bud cells of rat (13-day) and mouse (12-day) were subjected to culture for 5 days. The results showed that fluoride could inhibit differentiation of cells without affecting cells proliferation. The concentrations of 50% inhibition of cell differentiation (ID50) were 6.8 micrograms/ml(rat) and 7.3 micrograms/ml(mouse). The concentrations of 50% inhibitions of cell proliferation (IP50) were 44.1 micrograms/ml (rat) and 63.6 micrograms/ml (mouse). The IP/ID50 values 6.4(rat) and 8.7 (mouse) were both greater than 5. According to the assessment criteria of Flint and Cheng Wanrong, the fluoride may be an embryo limb bud cells specific inhibitor. It could have potent teratogenicity.

Animals↗
PubMed1998

[Malignant clonogenic precursors in the peripheral blood of patients with multiple myeloma].

OBJECTIVE: To study the clonogenic potential of circulating malignant precursors in the peripheral blood of patients with multiple myeloma (MM). METHODS: A new cell culture system was used to expand putative malignant precursor clones and promote their differentiation. Meanwhile, immunocytochemical staining, Giemsa-Wright staining and scanning electron microscopy were employed to reveal the growth properties and biological features of fresh and expanded malignant precursors and plasmacytes. RESULTS: Small lymphocyte-like B cells, which were actively proliferative and grew in the form of clusters, were found at the third day after culture. They accounted for 38% +/- 14%. The cells didn't express cytoplasmic immunoglobulin (CyIg) and CD38 antigen. In addition, no typical plasmacytes were observed. At the sixth day of culture, morphologically discernible plasmacytes, which grew in the form of large clumps in this culture system, were detected and represented 58% +/- 8%. These plasmacytes strongly expressed CD38 antigen and monoclonal CyIg identical to that of the original myeloma cells. CONCLUSION: Malignant clonogenic precursor cells, which have high proliferative potential, are present in the peripheral blood of MM cases, and could proliferate and differentiate into myeloma cells.

Adult↗
PubMed1998

[A study of motion perception in primary open-angle glaucoma].

OBJECTIVE: To study the characteristics of the motion perception (MP) in primary open-angle glaucoma (POAG). METHOD: Forty-one patients with POAG (67 eyes) and 56 (112 eyes) normal subjects were examined by the motion perception (MP) software in PC compatible computer. RESULTS: The total abnormal rate of MP was 89.5% in POAG, and 81.6% in the early stage of POAG. By using the grade correlation analysis, there is positive correlation of the abnormal degree of MP with C/D, ocular tension, and corrected loss variance (CLV) of visualfield, negative correlation of the abnormal degree of MP with visual acuity and visualfield mean sensitivity (MS), and no correlation of the abnormal degree of MP with age and short-term fluctuation (SF) of visualfield in the POAG patients. CONCLUSION: The examination of MP is a newly reliable and simple test for the diagnosis of the early POAG.

Adolescent↗
PubMed1998

[The testing of local electroretinogram in macular diseases].

OBJECTIVES: To record the local electroretinogram (LERG) in macular diseases, and define the using value of LERG in macular diseases. METHODS: The LERGs of five kinds of maculopathies were recorded with a spot light stimulator at 2.5, 5.0, 7.5 degrees of macular region. RESULTS: (1) The amplitudes of LERG at the three regions in Stargardt's disease, wet form age-related macular degeneration (AMD), central serous chorioretinopathy, and idiopathic macular hole were significantly lowered in comparison with the controls (P < 0.01). In the meanwhile, these diseases also showed high abnormal rates. While in dry form AMD and epiretinal membrane, the amplitudes of LERG had no significant changes (P > 0.05). (2) The abnormal rates of LERG were related to the stimulated area. In the three tested areas, the highest abnormal rates occurred at 2.5 degrees. CONCLUSIONS: There are mean differences in macular electrical activities in these maculopathies. LERG is an effective method of electrophysiology for testing macular function.

Adult↗
PubMed1998

[The fluorescein angiography and indocyanine green angiography of high myopia with macular hemorrhage].

OBJECTIVE: To investigate the causes and fundus changes of high myopia with macular hemorrhage. METHODS: Color photography and fundus fluorescein angiography (FFA) were performed on 35 patients (37 eyes) of high myopia with macular hemorrhages, and indocyanine green angiography (ICGA) was performed on 8 patients. RESULTS: The causes of high myopia with macular hemorrhage could be divided into two forms: (1) macular hemorrhage with subretinal neovascularization (23 eyes), (2) macular hemorrhage without subretinal neovascularization (14 eyes). ICGA noted the neovascularization more well-defined and slightly bigger than FFA. In 9 of 14 eyes, lacquer cracks appeared at the sites of macular hemorrhage or around the hemorrhage. 6 eyes were followed up, the follow-up period ranging from 3 to 20 months (mean, 8.6 months). ICGA was performed on two patients. The results show that the rupture of choriocapillaries and Bruch's membrane can result in hemorrhage without subretinal neovascularization, and ICGA is more sensitive in detecting the lacquer cracks than FFA. CONCLUSION: Subretinal neovascularization and the formation of lacquer cracks result in two forms of high myopia with macular hemorrhage. ICGA combined with FFA is more useful in evaluating the two forms of hemorrhage.

Adolescent↗
PubMed1998

[Analysis of oscillatory potentials of flectroretinogram].

This study presents a method for the analysis of oscillatory potentials (OPs) of electroretinogram (ERG) in frequency domain and time domain. OPs from 9 cases (9 eyes) of branch retinal vein occlusion, 9 cases (9 eyes) of central retinal vein occlusion and 40 normal control eyes were tested. The frequency spectra of the OPs were derived through Fast Fourier Transform. The mean frequency spectra, the total power, the maximum magnitude, the maximum power and the dominant frequency in frequency domain of the OPs were calculated. The OPs waveforms were re-constructed with the OPs frequency spectra data by counter-Fast Fourier Transform. In time domain, the latencies, the amplitudes and the sum of the amplitudes of the four peaks of OPs were measured.

Electrophysiology↗
PubMed1998

[Blossom and growth of pangdahai at Hainan Island].

Two species of Pangdahai--Scaphium lychnophorum Pierre and Scaphium wallichii Schoott & Endl. were introduced into Hainan Island in 1970s. Over a long-term observation and investigation at four different trial points, the results showed the main limited factor of the cultivation was typhoon; only in Nada area, northwest in Hainan Island, the upper two species grown well and bloomed after 14-16 years of planting, but not fruit. The analysis of the causes of the non-blossom and fruitlessness have also been made in this article.

Climate↗