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Biomedical subjects

J Yang

Publications and source records attributed to J Yang.

At least 325 records · Page 18Linked to original sources
PubMed2001

[Effect of phosphate on the exchangeable form and the bioavailability of exogenous neodymium in soil].

Effects of phosphate on the exchangeable form and the bioavailability of exogenous neodymium (Nd) in soil were studied with 147Nd isotopic tracer. Exchangeable Nd was extracted with solution (pH8.2) of NaAc. The results indicated that Nd beyond 99.5% was adsorbed by soil whether phosphate exists in soil or not. Phosphate can precipitate dramatically Nd3+. And the Nd phosphate precipitates may set limits on the concentration of exchangeable Nd observed in soil. KH2PO4 ranging from 0.3 g.kg-1 to 1.5 g.kg-1 make a uniform impact on the exchangeable form of Nd. In addition, phosphate in soil can inhibit wheat seedling to absorb Nd. The concentration of exchangeable Nd is correlated significantly with the content of Nd in wheat seedling.

Biological Availability↗
PubMed2001

Quantitation of neuroreceptors: a need for better SPECT imaging.

AIM: Existing methods to determine the binding potential in brain receptor and transporter studies with single-photon emission computed tomography (SPECT) show a marked dependence on the physical performance of the scanner and on the regions of interest (ROIs) drawn. We examined the influence of the physical performance on the binding potential. METHOD: The authors tested three gamma cameras (single-, dual- and triple-head) and two reconstruction techniques (conventional filtered back-projection and iterative reconstruction method) to determine the binding potential in brain receptor studies. Both human and organ-like phantom studies were performed. RESULTS: The binding potential was completely dependent on the imaging resolution, on the reconstruction technique used and on the ROIs drawn. The results of the phantom study revealed that the striatum-to-cerebellum ratio was only 37% of the actual one for the single-head, 63% for the dual-head and 72% for the triple-head gamma camera. CONCLUSION: The multiple head gamma camera with fan-beam collimators and iterative reconstruction with the attenuation based scatter correction is an imaging system of choice which introduces clinically more relevant images and is able to distinguish smaller differences in radioactivity at early stage of disease. However, for quantitative purposes the improvement without the use of the recovery coefficient is not great enough to restore the binding potentials to those of the true ones.

Brain↗
PubMed2001

[HCV core protein activates expression of vascular endothelial growth factor in HepG(2) cells].

OBJECTIVE: To explore the effect of HCV core protein on vascular endothelial growth factor (VEGF) in HepG(2) cells. METHODS: The HCV core gene cDNA was recoverd by PCR, and cloned into PBK-CMV. The recombinant plasmid (PBK-HCVc) and the vector-alone were transfected into HepG(2) cells with liposome. After being selected with G418,resistant colonies were obtained. The reverse transcription PCR and Western blot was analyzed to show HCV core protein expression. VEGF was analyzed by immunohistochemical and Western blot; VEGF mRNA was analyzed by in situ hybridization and reverse transcription PCR. RESULTS: The results suggest that the recombinant plasmid could express HCV core protein efficiently under the control of vector's promoter. The VEGF of HepG(2)-C cells was higher than that of HepG(2)-CMV. CONCLUSIONS: HCV C protein can activates the expression of VEGF in HepG(2) cells and may contributes to viral carcinogenesis.

Endothelial Growth Factors↗
PubMed2001

[Screening and characterization of human phage antibody to hepatitis C core antigen].

OBJECTIVE: To screen and characterize human phage antibody (ScFv) against hepatitis C core antigen. METHODS: The recombinant phages were panned by core antigen that was coated in a microtiter plate. After three rounds of biopanning, 48 clones were determined specific to core antigen. The specificity of each ScFv colone was determined by ELISA. The coding gene for HCV protein ScFv has been sequenced. RESULTS: Phage antibody for HCV core protein had a specific combination character with core antigen of hepatitis C virus. The DNA sequence data showed that the ScFv gene included 774 bp. CONCLUSIONS: Human single chain antibody to hepatitis C core antigen has been identified by means of the phage display technology.

Amino Acid Sequence↗
PubMed2001

Differences in attitudes toward organ donation among African Americans and whites in the United States.

The availability of organs within the African-American population has been an on-going issue. Historically, African Americans donate organs at a much lower rate than whites. Thus, this study was designed to compare general attitudes between African Americans, whites, and other minorities concerning the issue of organ donation and to identify the factors that hamper African Americans from becoming organ donors. We conducted a 12-question survey of 249 African Americans, 492 whites, and a category of others defining themselves as 71 Asians, 23 Hispanics, 22 Native Americans, and 35 unknowns for a total sample of 892. Samples were taken from six United States cities. Thirty-eight percent of African Americans stated they would not donate organs, compared to 10% of whites. When asked why not, African Americans stated "personal reasons" followed by "if I am an organ donor I won't get the necessary medical attention" as their top choices. Whites chose "religious reasons" followed by "organs may be taken before I am dead" as their top choices. African Americans were more concerned with getting proper medical treatment as opposed to whites, who worried their organs might be taken before their death. Regarding family discussion pertaining to organ donation, 66% of African Americans stated no discussion. Whites had a 46% rate for no family discussion. Regarding trust of doctors, 46% of African Americans expressed lack of trust for doctors, with 23% of whites expressing lack of trust for doctors. The results of this study point to the areas that must be given more focus by African-American health care providers and educators.

Adolescent↗
PubMed2001

[Diagnosis and treatment of pulmonary embolism during pregnancy].

OBJECTIVE: To study high risk factors, clinical presentation, diagnosis and treatment of pulmonary embolism (PE) during pregnancy and postpartum. METHODS: Two patients with pulmonary embolism were reported retrospectively. RESULTS: The 1st case was a pregnant woman with congenital heart disease at 39 weeks gestation, who underwent uneventful cesarean section (CS) because of heart disease, but she had tachycardia, tachypnea, cyanosis, dyspnea suddenly on the 10 days after CS and died immediately after the onset of above symptoms, the diagnosis of PE was highly suspected clinically. The 2nd case was a pregnant women with twin gestation, at 35 weeks, because of severe prenatal myocardiopathy, cesarean section was performed, Maternal death occurred suddenly during the surgery. The diagnosis of PE was confirmed by autopsy. CONCLUSIONS: The maternal mortality of PE during pregnancy and postpartum is very high, whenever there is any suspects, the objective examination for PE should be started early in order to get the chance to give anticoagulant therapy.

Adult↗
PubMed2001

Vitamin D receptor gene polymorphism and bone mineral density in patients with type 2 diabetes mellitus.

OBJECTIVE: To explore the relationship between vitamin D receptor (VDR) gene polymorphisms and bone mineral density (BMD) in patients with type 2 diabetes mellitus (DM) and to better understand the pathogenesis of osteoporosis. METHODS: Ninety seven patients with type 2 DM were recruited for this study. BMD was measured by single photon absorptiometry at the lower one third of the nondominant radius and ulna. Polymorphisms of the VDR gene were analyzed by DNA amplification with polymerase chain reaction (PCR) and endonuclease digestion with Bsm I. RESULTS: The respective frequencies of VDR genotypes were BB 18.6%, Bb 27.8% and bb 53.6%. The Z scores of the three groups were -1.57 +/- -0.60, -1.45 +/- -0.67 and -1.41 +/- -0.81, respectively. Although the BMD of the Bb genotype DM patients was higher than that of BB genotype DM patients and lower than that of bb genotype DM patients, there were no significant differences. CONCLUSION: These findings suggest a small influence of VDR gene polymorphism on the BMD of patients with type 2 DM. Further study on the value of VDR genotypes in the pathogenesis of osteoporosis in diabetes mellitus is still needed.

Adult↗
PubMed2001

Effect of theophylline on airway inflammation in asthma.

AIM: To investigate whether low dose theophylline has an anti-inflammatory effect in asthma. METHODS: Nineteen asthmatic subjects were given 200 mg sustained-release theophylline preparation twice daily for 4 weeks. The mean serum concentration of theophylline was 7.9 mg/L. The percentage of eosinophils, EG2+ eosinophils, and the level of eosinophil cationic protein (ECP) in sputum pre- and post-administration were detected by Wright's stain, immunocytochemistry, and immuno-CAP system, and the symptom scores and lung function were evaluated as well. The above indices for 10 healthy subjects were regarded as control. RESULTS: Before using theophylline, sputum eosinophils, EG2+ eosinophils, and ECP in asthmatic group were much higher than those of healthy group. After four weeks administration, there were great decreases in percentage of total eosinophils (40 % +/- 17 % vs 29 % +/- 11 %, P < 0.01), activated (EG2+) eosinophils (28 % +/- 9 % vs 10 % +/- 8 %, P < 0.01) and in the concentration of sputum ECP [(373 +/- 206) vs (220 +/- 132) microg/L, P < 0.01]. The symptom scores decreased greatly (7.1 +/- 1.2 vs 5.4 +/- 1.6, P < 0.01). There was a marked increased in forced expiratory volume one second (FEV(1.0)) after administration (2.2 +/- 0.6 vs 2.4 +/- 0.5, P < 0.01). The FEV(1.0) % of asthmatic subjects after administration increased (60 % +/- 13 % vs 65 % +/- 13 %, P < 0.01), too. CONCLUSION: These results indicated that low dose theophylline had inhibitory action on airway inflammation in asthma with noticeable improvement of the patients' symptoms and lung function.

Adult↗
PubMed2001

Improvement of melatonin to the learning and memory impairment induced by amyloid beta-peptide 25 - 35 in elder rats.

AIM: To investigate improvement of melatonin on learning and memory impairment induced by amyloid beta-peptide 25 - 35 (Abeta25-35) in elder rats. METHODS: Step-down type passive avoidance test, shuttle-box test, and Morris water maze were used together to determine effects of Abeta25-35 and melatonin on learning and memory. Pathological changes were observed by HE, Congo red, and Ag staining. RESULTS: The elder rats were injected bilaterally Abeta25-35 20 microg into the hippocampus to induce learning and memory dysfunction. Melatonin administration (0.1, 1, and 10 mg/kg, ig x 8 d) to the Abeta25-35-treated rats prolonged the latency, shortened the total stimulating time, and decreased the number of errors in the step-down test. Shuttle-box test showed that melatonin improved amnesic rats' performance at the same doses. Melatonin (0.1, 1, and 10 mg/kg ), giving for 10 d, could enhance the spatial resolution of amnesic rats in Morris water maze test. Also in Abeta25-35-treated group, a decrease in the number of neurons in cortex and hippocampus, a massive glial reaction, and neurophilic phenomenon were detected by HE staining; the positive vascular amyloidosis by Congo red and fibrils by Ag staining were observed. Melatonin (0.1 and 1 mg/kg)could inhibit above pathological changes in Abeta25-35 group. CONCLUSION: Melatonin improved the impaired learning and memory induced by Abeta25-35 in elder rats.

Amyloid beta-Peptides↗
PubMed2001

[Sleep-breathing disordered in stable chronic congestive heart failure].

OBJECTIVE: To determine the prevalence and effect of sleep-disordered breathing in patients with stable, optimally treated chronic congestive heart failure. METHODS: Patients with stable, optimally treated chronic congestive heart failure were monitored by polysomnography (Polywin 1000, Respironics Inc.). RESULTS: Patients were divided into two groups. Group I (n = 21) had a rate of apnea and hypopnea (apnea-hypopnea index) of 15 or less episodes per hour; group II (n = 15) had a rate of more than 15 episodes per hour. In group II, the rate varied from 16.8 to 78.8 episodes per hour 42.6 +/- 15.5, in which the obstructive apnea-hypopnea index was 11.1 +/- 8.4 and the central AHI was 31.5 +/- 9.6. Group II had significantly more arousals (36.8 +/- 21.3 compared with 19.4 +/- 11.2 in group I) that were directly attributable to episodes of apnea and hypopnea, lower arterial oxyhemoglobin saturation during sleep [(76.7 +/- 4.6)% compared with (86.5 +/- 2.8)%] and lower left ventricular ejection fraction [(24.2 +/- 8.8)% compared with (31.5 +/- 10.6)%]. CONCLUSIONS: The prevalence of sleep-disordered breathing (mainly periodic respiration or Cheyne-Stokes respiration with central sleep apnea) is high in patients with stable chronic congestive heart failure. The sleep-disordered breathing episodes are associated with severe nocturnal arterial blood oxyhemoglobin desaturation and excessive arousals. Severe untreated sleep-disordered breathing may affect left ventricular function and could contribute to death in patients with congestive heart failure.

Aged↗
PubMed2001

[Effect of pH on nodulation of soybean rhizobia from Weifang and Huayuankou soils].

The effect of pH on the nodulation of Sinorhizobium fredii and Bradyrhizobium japonicum was examined by analyzing the indigent soybean rhizobia, predominant indigent rhizobia, and specific rhizobia, respectively. The results showed that very acid and very alkaline environment could retard the nodulation and inhibit the growth of the rhizobia. Sinorhizohium fredii could endure environment more strongly than Bradyrhizobium japonicum, and had a high competitive nodulation capacity. Bradyhizobium japonicum could endure acid environment more strongly than Sinorhizobium fredii. In very acid and very alkaline environment, the nodulation capacity of S. fredii and B. japonicum was mainly determined by their physiological characteristics.

Bradyrhizobium↗
PubMed2001

[Water distribution and microclimatic effects of sprinkler irrigation on spring wheat field].

Measurements of sprinkler irrigation on spring wheat field indicated that spring wheat canopy could intercept water by 25-30%, and compared with that above canopy in first milking period, the uniformity coefficient below canopy could be increased by 7-9%. Floating and evaporation loss of sprinkler irrigation water could reach 20-25% of the total. In addition, sprinkler irrigation on spring wheat field could decrease air and soil temperature, and increase air actual vapor pressure and relative humidity, which played a definite role in restraining crop transpiration.

Microclimate↗
PubMed2001

[Study on improvement of cell affinity of polymer materials--modified poly(D,L-lactide) by anhydrous ammonia gaseous plasma].

OBJECTIVE: To modify the surface of poly(D,L-lactide) film by anhydrous ammonia gaseous plasma treatment. METHODS: The changes of contact angles were measured and surface energy were calculated. Mouse 3T3 fibroblast cells were cultured on plasma modified and control poly(D,L-lactide) films. RESULTS: It was found that the hydrophilicity and surface energy of the materials have been increased after plasma treatment. Cell culture results showed that ammonia plasma treatment could promote the cell attachment and cells growth. After 4 days culture, the cells on the plasma treated films were 2-folds quantitatively compared with that of the control films. CONCLUSION: Ammonia plasma treatment can improve the cell affinity to poly(D,L-lactide).

3T3 Cells↗
PubMed2001

[An investigation on morphology of experimental corneal neovascularization].

OBJECTIVE: To observe the morphologic character of the corneal neovascularization in experimental rabbits and also compare it with the morphology of that after irradiation with beta-rays. METHODS: A model of new blood vessels on the corneas of New Zealand rabbits was established with silver nitrate burning. The growth character of the neovascularization was compared between the irradiated and non-irradiated groups. The casting of the new blood vessels in different periods was made and the morphologic differences between the two groups were compared under a scanning electron microscope. RESULTS: The corneal new blood vessels occurred and continuously proliferated with the typical method of budding. The formation of buds was obviously inhibited and damaged after irradiation with &#61538 or &#61485 beta-rays, and the irradiated new branches were also atrophic and necrotic. CONCLUSIONS: Stopping the budding procedure of the corneal neovascularization may inhibit the formation and development of the corneal new blood vessels.

Animals↗
PubMed2001

[Association between dopamine transporter gene polymorphism and Parkinson's disease].

OBJECTIVE: To detect the association between dopamine transporter gene polymorphism and Parkinson's disease (PD). METHODS: The authors analyzed the difference in the distribution of the variable number tandem repeat (VNTR ) polymorphism within the 3' untranslated region of the DAT gene between 85 normal controls and 128 PD patients that were further divided into the senile subgroup (aged >50 years at onset of PD ) and the early-onset subgroup (aged </=50 years). RESULTS: There were significant differences in genotypic and allelic distribution between the control group and the PD group. The senile PD was strongly associated with the 7-copy allele and weakly with the 10-copy allele, and the early onset PD was mainly associated with the 9-copy allele. CONCLUSION: The findings not only support an association between DAT gene and PD but also suggest the relationship of the 3'VNTR polymorphism of DAT gene with the age at the onset of PD.

Adolescent↗
PubMed2001

[Analysis on HLA-E polymorphism in Shanghai Han population].

OBJECTIVE: To investigate the distribution of HLA-E alleles in Chinese Han in Shanghai area. METHODS: HLA-E alleles were assigned by using a PCR/SSO method in 201 random healthy individuals from Shanghai region. HLA-A,-B antigens typing was carried out with NIH standard microlymphocytoxicy method. RESULTS: Three alleles of HLA-E could be detected in this population. The E*0101 is the most common allele with a frequency of 42.29%, followed by E*01032 and E*01031 with 32.84% and 24.88% respectively. No E*0102 and E*0104 could be detected in all of the individuals. The analysis of linkage on two loci between HLA-E and HLA-A or -B showed that no significant difference could be found between expected frequencies and observed frequencies excepting B15/E*01032 and A2/E*01032. CONCLUSION: The allele frequencies of HLA-E are 42.29% for E*0101, 24.88% and 32.84% for E*01031 and E*01032 respectively in Shanghai Chinese. No extensive linkage disequilibrium was found between HLA-E and HLA-A or -B locus.

Alleles↗
PubMed2001

Arsenic trioxide induces multiple myeloma cell apoptosis via disruption of mitochondrial transmembrane potentials and activation of caspase-3.

OBJECTIVE: To investigate the response of multiple myeloma (MM) cells to arsenic trioxide (As2O3) and their possible mechanisms. METHODS: Two MM-derived cell lines RPMI8226 and U266 cells were used as in vitro models. Cell apoptosis was assessed by morphology, flow cytometry, and DNA gel electrophoresis. Mitochondrial transmembrane potentials (delta psi m) were evaluated by measuring cellular Rhodamine 123 staining intensity. Protein expression was analyzed using Western blot. RESULTS: Zero point one to 0.5 mumol/L As2O3 inhibited cell proliferation and 2.0 mumol/L As2O3 induced cell apoptosis, while 1.0 mumol/L As2O3 inhibited proliferation with a weak degree of apoptosis induction in RPMI8226 and U266 cell lines. As2O3-induced apoptosis was accompanied by mitochondrial transmembrane potentials (delta psi m) collapse and caspase-3 activation in the presence of intact membrane. Glutathione depleter buthionine sulfoximine enhanced, while disulfide bond-reducing agent dithiothreitol partially antagonized As2O3-induced delta psi m collapse and apoptosis in MM cells. All-trans retinoic acid (ATRA) could also induce apoptosis in RPMI8226 cells, but it did not show any cooperative effects with As2O3. CONCLUSION: As2O3 exerts apoptosis-inducing and growth-inhibiting effects on MM cells, and mitochondrium is a pivotal and common target of As2O3 for apoptosis induction.

Antineoplastic Agents↗