Biomedical subjects

R Wang

Publications and source records attributed to R Wang.

At least 145 records · Page 8Linked to original sources

PubMed2001

[Changes in the state of phosphorylation of DARPP-32 of gerbil striatum during ischemia].

Using the mongolian gerbil model of transient forebrain ischemia by bilateral carotid arteries occlusion, the levels of phosphorylation and the amount of DARPP-32 in striatum were measured by back-phosphorylation and Western-blotting assay in vitro. Transient forebrain ischemia had no effect on the immunoreaction of DARPP-32 in striatum, but the state of phosphorylation of DARPP-32 showed a significant change. The [32P] phosphate incorporation in DARPP-32 decreased after 2, 7 or 10 min of ischemia, but increased after a 5-min ischemia. In contrast, the result of back-phosphorylation in vivo was opposite to that obtained in vitro.

Animals↗

PubMed2001

Adenovirus-mediated expression of a truncated PDGFbeta receptor inhibits thrombosis and neointima formation in an avian arterial injury model.

Platelet-derived growth factor (PDGF) is a major mediator of neointima formation after arterial injury. We constructed a recombinant adenovirus, Ad/PDGFtr, that expresses the soluble extracellular domain of the murine PDGFbeta receptor (PDGFtr). The expressed PDGFtr was appropriately glycosylated and secreted by chicken vascular smooth muscle cells (SMCs) in vitro. The expressed PDGFtr inhibited human PDGF-BB induced receptor autophosphorylation, and also inhibited PDGF-BB induced cell proliferation without affecting PDGF-AA induced mitogenesis. In vivo transduction of balloon-injured rooster femoral arteries with Ad/PDGFtr resulted in expression and secretion of the glycosylated PDGFtr. The expressed PDGFtr significantly inhibited neointima formation compared with controls. Neointima-associated thrombus was significantly reduced in Ad/PDGFtr transduced arteries compared with controls. Thus, in addition to impacting on SMC proliferation and migration, PDGF-BB plays a role in thrombus formation in response to arterial injury. Growth factor inhibition by localized gene delivery constitutes a powerful approach to intervene in the molecular pathways involved in vascular disease.

Animals↗

PubMed2001

[Ectopic expression of human brain derived neurotrophic factor gene in fibroblasts].

The full-length sequence encoding hBDNF was inserted down into the enhancer-promotor regulatory element of Colia1 to construct minigene Colia1-BDNF. The recombinant eukaryotic expression plasmid pSCEPBFCAT was transfected into human fetal tendon fibroblasts in culture to realize ectopic expression of hBDNF gene in fibroblasts. The results of immuno-dot blot, Elisa and Western hybridization confirm that the expression protein with apparent molecular weight 27 kDa in pSCEPBFCAT transfected fibroblasts possesses antigen activity specific for the antibodies to BDNF.

Brain-Derived Neurotrophic Factor↗

PubMed2001

[Comparison study between biological vision and computer vision].

The development and bearing of biology vision in structure and mechanism were discussed, especially on the aspects including anatomical structure of biological vision, tentative classification of reception field, parallel processing of visual information, feedback and conformity effect of visual cortical, and so on. The new advance in the field was introduced through the study of the morphology of biological vision. Besides, comparison between biological vision and computer vision was made, and their similarities and differences were pointed out.

Aerospace Medicine↗

PubMed2001

Eye irritation caused by formaldehyde as an indoor air pollution--a controlled human exposure experiment.

OBJECTIVE: The present study focuses on health assessment of wood based panels which are widely used in interior decoration practices over the recent years in China. Formaldehyde has been identified as chemical indicator of (IAO) and an indoor air pollutant. To test its health effects experiment was undertaken. METHOD: A small environmental test chamber (60/L) was used as the generator of emission gas from new panels, and was operating at a temperature of 22.7 +/- 0.6 degrees C and a humidity of 44.4 +/- 2.5% with an air exchange rate of 1.0 +/- 0.15 h-1. On the three experimental days the values of product loading in chamber were 4, 2 and 6 m2/m3, respectively. Eight people were selected randomly from the students and employees of Wuhan Health and Anti-epidemic Station as subjects, with an average age of 21.9 +/- 5.9 years, and a gender ratio of 1:1, and two of them were smokers (one male and one female). The subjects' eyes were exposed to formaldehyde through a pair of goggles. Each goggle had its flow inlet and outlet, and connected to chamber exhaust of emission gas and to an exhaust from the room. The exposure time was very short, just 5 minutes and the formaldehyde doses were at 1.65 +/- 0.01, 2.99 +/- 0.07 and 4.31 +/- 0.02 ppm. A 60-mm linear visual analogue rating scales was used to measure the intensity of sensory eye irritation and a video tape recorder was used to record eye blinking frequency. RESULTS: The results demonstrated that tests of sensory eye irritation and eye blinking can be used for materials testing, and that a dose-effect as well as a time-variance of the effect can be measured. CONCLUSION: The tests showed that eye irritation was perceived at all of the three levels.

Adolescent↗

PubMed2001

[Changes of photosynthetic characteristics of strawberry leaf under shading].

Studies on the photosynthetic characteristics of two strawberry varieties (Baojiaozaosheng and Shuofeng) under shading showed that the photosynthesis rate decreased by 20% and 47%, when the apparent quantum efficiency increased by 13% and 8%, respectively. The chlorophyll content was enhanced slightly, while the insoluble protein content in leaf decreased drastically. The results also showed that the PSII activity decreased by 22.5% and 53.7%, and the activity of Rubisco, the key enzyme of Calvin cycle, decreased by 19.6% and 35.5%, respectively. The reason of photosynthesis rate descent in light saturation point was also discussed.

Light↗

PubMed2001

[Comparative study on clonal and sexual reproductive traits of Leymus chinensis populations in different habitats].

The variations of clonal and reproductive traits between four Leymus chinensis populations in different habitats were studied on northeast grasslands of China. The results showed that significant differences existed among Leymus chinensis populations in both clone traits (vegetative shoot densities and tiller densities) and sexual reproduction traits (reproductive shoot densities, reproductive shoot differentiation and reproductive effects), primarily due to the habitat heterogeneity of sites, especially the difference in soil moisture. The difference between grassland population and dune population was relatively greater, and the average vegetative shoot density, tiller density and sexual shoot density from grassland population were 50%, 30% and 200% greater than those from dune, respectively.

Ecosystem↗

PubMed2001

[Caloric value and energy allocation of Chloris virgata in northeast grassland].

The rules of seasonal changes in caloric values of individual plant, stem, and leaves of Chloris virgata were similar, which had two peak values from early July to early August, and then decreased gradually. Those of inflorescence assumed U shape, and had two peak values in early August and middle September, respectively. The seasonal changes in caloric values of dead standing were irregular, and the maximum value was appeared in early August. The seasonal changes in existent energy value of the aboveground parts in Chloris virgata population presented double peak curve. The two peak values were appeared in early August and early September respectively, and the maximum value was 7381.27 kJ.m-2 in early September. The energy allocation in different seasons was leaf > stem in early July, stem > leaf > dead standing in middle July, stem > leaf > inflorescence > dead standing in August, stem > inflorescence > leaf > dead standing in early September, and stem > inflorescence > dead standing > leaf in middle September. The vertical structure of energy in the aboveground parts was that the energy value gradually increased from the earth's surface to 20 cm high, and then decreased. The maximum value, which accounted for 25.75% of energy in the aboveground parts, was appeared in the layer of 10-20 cm high. In the underground parts, the energy value progressively decreased with the increase of depth, and the maximum value, which accounted for 74.21% of energy in the underground parts, was appeared in the layer of 0-10 cm depth.

Energy Metabolism↗

PubMed2001

[Effect of rice canopy structural changes on bidirectional reflectance].

The study of vegetation bidirectional reflectance is useful for remote sensing data interpretation. Vegetation canopies information such as leaf area index, mean leaf inclination, mean plant height, and coverage, can be inverted from vegetation bidirectional reflectance. This paper discussed the dynamics of vegetation canopies reflectance with vegetation canopy structures by measuring rice canopy structure and bidirectional reflectance at 26, 35, 41, 49, 62, 67 and 86 days after transplanting. It is concluded that the sensitivity of vegetation canopies to directional reflectance variations varied with canopy structures, and hence, through bidirectional reflectance, more information about canopy structure can be know.

Light↗

PubMed2001

A hybrid learning network for shift, orientation, and scaling invariant pattern recognition.

A three-layer neural network is presented as a generic approach for visual pattern recognition invariant with respect to the geometric appearance such as translation, orientation and scale of the patterns. The invariant recognition is achieved by representing the geometric variations internally in the network by nodes in the input and middle layers, which are laterally connected and trained by a hybrid algorithm combining both competitive and Hebbian learning. As the result of the hybrid learning, each pattern will be represented by a particular subset of middle-layer nodes all specialized to respond to the same pattern but with different geometric appearances. The nodes in the output layer are then trained by competitive learning to recognize the different pattern internally represented by the middle-layer nodes, independent of their location, orientation and size. The proposed algorithm is generic and robust and can be applied to various practical recognition problems. Moreover, the network is relatively simple and biologically plausible and can serve as a computational model to account for the invariant object recognition in the biological visual system.

Algorithms↗

PubMed2001

192Ir endovascular irradiation prevents restenosis after balloon angioplasty in rabbit.

OBJECTIVE: To examine the effect of endovascular irradiation on restenosis after balloon angioplasty in rabbit. METHODS: After the establishment of rabbit iliac atherosclerosis model, balloon angioplasty was performed at the lesion segment of the iliac artery. Rabbits were randomly divided into three groups: control group, 10 Gy irradiated group and 18 Gy irradiated group. Endovascular irradiation was performed for irradiated groups at the dilated sites by introducing the 192Ir radioactive guidewire through a catheter. After four weeks, the animals were killed and the target segments were cut down. Histopathologic and morphometric analyses were carried out. RESULTS: The mean final lumen area in the 18 Gy group was larger than that in the control or 10 Gy group (P < 0.05). The intimal area in the 18 Gy group was smaller (P < 0.05). CONCLUSIONS: 192Ir endovascular irradiation may prevent restenosis after balloon angioplasty. The effect is related to the delivered dose. The mechanism is involved in inhibition of neointimal proliferation.

Angioplasty, Balloon↗

PubMed2001

Percutaneous balloon aortic valvuloplasty in the treatment of congenital valvular aortic stenosis in children.

OBJECTIVE: To assess the effect of the balloon valvuloplasty for for congenital valvular aortic stenosis (AS) in children. METHODS: A total of 27 (mean age 6.09 years) children with AS accepted the treatment of percutaneous balloon aortic valvuloplasty (PBAV). The ratios of balloon/valve were 0.95 +/- 0.08 for 19 cases of typical AS and 1.00 +/- 0.11 for 8 cases of hypoplastic AS. The patients were evaluated by the gradients across aortic valves in pre- and post-PBAV and by echocardiogram during the follow-up period. RESULTS: Fifteen of 19 (78.9%) cases of typical AS had a better outcome and the gradient of the remaining 4 cases (26.7%) had increased after follow-up (delta P > 50 mm Hg). Four of 8 (50.0%) cases of hypoplastic AS had satisfactory responses and the gradient of the remaining 3 cases (75.0%) rose. There was no moderate to severe aortic insufficiency (AI). CONCLUSION: The balloon aortic valvuloplasty provides safe and significant hemodynamic and clinical improvement in pediatric patients. The outcome of PBAV for typical AS is better than for hypoplastic AS.

Adolescent↗

PubMed2001

Percutaneous balloon angioplasty of coarctation of the aorta in children: 12-year follow-up results.

OBJECTIVE: To evaluate the efficiency of percutaneous balloon angioplasty of coarctation of the aorta in children and discuss its risk factors that can lead to poor long-term results. METHODS: From September 1987 to August 1999, 24 patients underwent 27 balloon angioplasty procedures for native or recurrent coarctation of the aorta at our institution. There were 19 patients with discrete (membranous) coarctation, 4 patients with long-segment and aortic arch hypoplasia, and 1 patient with postoperative recurrence. The balloon diameter was chosen not to exceed the diameter of the aorta proximal to the stenotic site (11.06 +/- 2.80 mm vs 11.78 +/- 3.18 mm), with the chosen diameter two to four times that of the stenotic segment (2.57 +/- 0.68 times). The patients have been followed up for half to twelve years (mean 6.2 +/- 2.8 years). Satisfactory result was defined as a reduction in the pressure gradient across the site of coarctation to < or = 20 mm Hg. RESULTS: The systolic pressure gradient across the coarctation site decreased from 48.17 +/- 14.68 mm Hg to 14.96 +/- 13.12 mm Hg (P < 0.01) and the diameter of the coarctation site increased from 4.66 +/- 2.43 mm to 8.80 +/- 3.32 mm (P < 0.01). Immediate satisfactory results were obtained in 19 patients (79%). Of the 5 patients with unsatisfactory results, 4 had aortic arch hypoplasia and 1 had membranous coarctation. Of the 19 patients with satisfactory results, 18 patients had membranous coarctation and 1 patient had recurrent postoperative coarctation. No aneurysm and other complications had occurred in any patients at the follow-ups. CONCLUSION: Percutaneous balloon angioplasty is an effective treatment alternative to surgery in most patients with recurrent postoperative or native membranous coarctation of the aorta. It should not be recommended for the coarctation of aortic arch hypoplasia.

Adolescent↗

PubMed2001

[Orthokeratology induced infective corneal ulcer].

OBJECTIVE: To investigate the clinical course, treatment and outcome of infective corneal ulcer induced by orthokeratology. METHODS: Sixteen cases of infective corneal ulcer caused by orthokeratology were reported, including 7 cases of pseudomonas corneal ulcers, 8 cases of acanthamoeba keratitis and 1 case of mycotic keratitis. Smears and cultures from corneal scrapings for bacteria, fungi and amoeba were performed for all of the patients. According to the results of pathogenic microorganisms, different therapeutic approaches were given. Lamellar keratoplasty or penetrating keratoplasty was performed for 9 patients whose corneal lesions were serious and unresponsive to medical therapy. RESULTS: After medical treatment or keratoplasty, corneal infections of all the patients were controlled. The visual acuity of most cases was improved. CONCLUSIONS: The infective corneal ulcer is the most serious complication of orthokeratology. The treatment of infective corneal ulcer should be directed toward the elimination of the pathogenic microorganisms from the cornea. Keratoplasty continues to have a central role in the management of some advanced cases. Although the infections can be controlled, the vision of these patients is seriously damaged.

Acanthamoeba Keratitis↗

PubMed2001

Human movement characteristics of target acquisition.

Objective. This paper deals with the problem of human movement characteristics of target acquisition. Method. A hypothetical model was posed by using experimental data. Result. The conception of final target size was put forward, an equation for calculating the movement time of target acquisition was obtained, and a new definition of index of difficulty was given. Conclusion. Analysis of experimental data showed that this equation could give a better description of target acquisition in a wide range.

Acceleration↗

PubMed2001

[Application of the interaction models between the polymorphism(s) of metabolic gene(s) and environmental exposure].

OBJECTIVE: Taking GST M1 as an example to introduce analytic method of interaction models between the polymorphism(s) of metabolic gene(s) and environmental exposure in stomach cancer susceptibility. METHODS: Using community-based case-control design, combined with molecular biological techniques (PCR) and multiple variables logistic regression models, we analyzed 112 intestinal types of stomach cancer cases with endoscopy and pathology diagnosis in the Yangzhong City Hospital during January 1997 and December 1998. A total of 675 controls were selected from persons who had no history of digestive system cancers. RESULTS: After adjustment of confounding variables with both GST M1 null genotype and history of ever tobacco smoking, the results showed a significant types of 4 gene-environment interaction. Interaction index (gamma) value was 3.38 and OR(eg) value was 8.40, suggesting that a super multiplicative interaction occurred. The results also showed that GST M1 null genotype had a high exposure-gene effect interaction with tobacco smoking (pack year), while gamma values were 0.995, 2.085 and 2.157 respectively. A low exposure-gene effect interaction was found in GST M1 null genotype with the amount of (kg x year) alcohol consumption while gamma values were 1.01 and 0.97 respectively. CONCLUSION: Logistic regression model can be used to evaluate gene-environment interaction and dose-response of exposure-gene effect.

Alcohol Drinking↗

PubMed2001

[Seroepidemiological analysis of characteristic of hepatitis B virus in children after vaccination in Ningbo].

OBJECTIVE: To understand the immunity of children in Ningbo after hepatitis B vaccination for seven years and to explore the best time for booster. METHODS: One thousand nine hundred and twenty serum samples from children born in 1982 - 1995 were tested for anti-HBs and HBsAg, using RIA. RESULTS: (1) HBsAg positive rate (2.66%) was lower in vaccinated children born in 1992 - 1995 than those unvaccinated (10.92%) born in 1982 - 1995. HBsAg positive rate had a drop of 75.71% (chi(2) = 22.91, P < 0.0001). (2) Anti-HBs positive rates (65.95%) in vaccinated children was much higher than that in unvaccinated children (41.03%) (chi(2) = 113.67, P < 0.0001). (3) It also showed that children's positive rate of HBsAg increased and anti-HBs dropped after 5 - 7 years of vaccination. CONCLUSION: After immunization of hepatitis B vaccine for 7 years, high immunity and low infection rate of HB in children it appeared in Ningbo. However it is necessary to further study the reason causing the increase of HBsAg positive rate and/or deerease of anti-HBs positive rate, and the suitable time frame of boostering, after 4 or 5 years of primary vaccination.

China↗

PubMed2001

[The effects of astragalus and shenmai injections on macrophage function in burned mice].

OBJECTIVE: To explore the dynamic postburn change in macrophage function in burned mice within 120 hrs after injury, and to investigate the effects of astragalus and shenmai injections on the macrophage function and surrvival rate of burned mice. METHODS: The mice were divided into 13 groups according to postburn time and handling methods, i,e, normal control (A), burn control (B), normal mice with astragalus (NA), normal mice with shenmai (NS), burned mice with astragal (BA), burned mice with shenmai (BS) 2 postburn hour (2 PBH), 6 PBH, 12 PBH, 24 PBH, 48 PBH, 72 PBH, 120 PBH groups. The changes in the various macrophage functions at different postburn time points and after the use of astragalus and shenmai injections were determined by means of phagocytic and RT-PCR methods. RESULTS: (1) Within 120 PBHs, the phagocytic function of murine macrophages decreased evidently. The ACP activity decreased obviously. The expression of IL-15 mRNA fluctuated and that of TNF mRNA enhanced significantly. (2) Five days after the application of astragalus in dose of 2 500 mg . kg(-1) .d(-1), the phagocytic function of macrophages and ACP activity increased markedly (P < 0.01). The expressions of IL-15 and TNF mRNAs were not influenced. The survival rate of mice was not increased. (3) Five days after the application of shenmai injection in dose of 2.5 ml . kg(-1) . d(-1), the phagocytic function of macrophages and ACP activity increased significantly (P < 0.01), while the expression of IL-15 mRNA exhibited no change. But the expression of TNFalpha mRNA decreased obviously (P < 0.01). Moreover, the survival rate of burned mice was evidently raised (P < 0.05). CONCLUSION: Peritoneal administration of shenmai injection at early postburn stage could significantly improve the macrophage function of burned mice, and it increase the survival rate of mice.

Acid Phosphatase↗