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Biomedical subjects

Y Yang

Publications and source records attributed to Y Yang.

At least 289 records · Page 16Linked to original sources
PubMed2001

Neuronal apoptosis resulting from high doses of the isoflavone genistein: role for calcium and p42/44 mitogen-activated protein kinase.

Genistein is a potent plant-derived isoflavone displaying estrogenic activity at low (nanomolar) concentrations and antiproliferative and antiangiogenic properties at higher concentrations (above 10-50 microM). The antiproliferative potential of genistein has made it an interesting candidate for cancer chemotherapy at high concentrations; however, the potential for genistein toxicity in neurons at such concentrations has not been previously addressed. We show that genistein is toxic to rat primary cortical neurons at a concentration of 50 microM, whereas daidzein, a structural analog, shows no toxicity at similar concentrations. The dying cells display an apoptotic morphology that is characterized by fragmented nuclei, appearance of apoptotic bodies, DNA laddering, and caspase-dependent poly(ADP-ribose) polymerase cleavage. This cell death is partially dependent on caspase activity, independent of estrogen receptors, and does not result in a significant loss of Bcl-2 or Bcl-X(L) protein. Genistein exposure induces delayed and prolonged activation of p42/44 mitogen-activated protein kinase (MAPK) and p38 MAPK but not c-Jun NH2-terminal kinase. The specific p42/44 MAPK kinase inhibitor PD98059 (50 microM) partially blocks genistein-induced apoptosis, whereas the p38 MAPK inhibitor SB202190 (10 microM) has no effect. Genistein elevates intracellular calcium and both 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester (1 microM) and dantrolene (10 microM) inhibit genistein-induced apoptosis, suggesting a link between genistein-induced intracellular calcium release and apoptosis. The combination of dantrolene and PD98059 block genistein-induced apoptosis in an additive manner compared with either compound alone. These findings provide evidence for a proapoptotic function of p42/44 MAPK and raise caution about potential side effects in the nervous system with genistein use as a high-dose therapeutic agent.

Animals↗
PubMed2001

[The association between SA gene and essential hypertension in Han Chinese].

OBJECTIVE: To evaluate the linkage of SA gene locus to essential hypertension(EH) in affected Han Chinese sib pairs and to ascertain the association of SA gene CT79 polymorphism with essential hypertension in Han Chinese hypertensives. METHODS: In Han Chinese at Shanghai, 96 random individuals, 80 essentially hypertensive sib pairs with hypertensive family history, 200 essential hypertensives with hypertensive family history and 200 normotensive control(NC) subjects without such family history were enrolled in these serial studies. MF-PCR-SSCP technique was applied to detect the frequency distributions of SA gene microsatellite D16S3046, D16S3136 and D16S3068. The linkage of SA gene locus to essential hypertension was analyzed by Green's IBS for affected siblings. SA gene variant was screened by PCR-SSCP- silver staining and confirmed by DNA sequencing, then an association study was performed to determine whether such variant was associated with essential hypertension. RESULTS: The frequency distributions of SA gene microsatellites D16S3046, D16S3136 and D16S3068 were of high polymorphism. The polymorphism information contents of D16S3046, D16S3136 and D16S3068 were 0.86, 0.82 and 0.80, and the heterozygosities 0.88, 0.71 and 0.77. The linkage of SA gene locus to essential hypertension was not observed; the linkage analysis t values of D16S3046,D16S3136 and D16S3068 were 0.972, 0.622 and 0.236, and the P values 0.384, 0.543 and 0.871, respectively. The C two head right arrow T substitution was confirmed, but there was no association of such variant with essential hypertension. The frequency distributions of genotypes and alleles in the hypertensive group were not significantly different from those in the normotensive group (P>0.05). CONCLUSION: SA gene is not linked to or associated with essential hypertension in Han Chinese. SA gene may not be a susceptible gene contributing to the development of essential hypertension in Han Chinese.

Adult↗
PubMed2001

[The outlook of using chitosan related materials in nerve regeneration].

Chitosan is a kind of biodegradable materials with excellent biocompatibility. This article interpreted the progress and outlook of using chitosan related materials in nerve regeneration from the following points: the positive charges on chitosan, its ability to adsorb proteins, the specific adhesion of nerve cells on chitosan, and the surface roughness, aperture and surface topography of chitosan.

Biocompatible Materials↗
PubMed2001

Transgenic mice with overexpression of human scavenger receptor A on endothelial cells.

OBJECTIVES: To establish a new transgenic mouse model for determining the function and role of human scavenger receptor A (SR-A) in atherosclerosis in vivo. METHODS: Human scavenger receptor minigene-driven mouse tie-1 promoter was constructed and confirmed by endonuclease digestion and sequence analysis. Transgenic mice were generated via the microinjection method. PCR and Southern blot were used to screen the positive transgenic mice. RT-PCR and immunohistochemical analysis were used to detect the level and location of human SR-AI expression in transgenic mice. The activity of human SR-AI was determined by morphologic observation of aortic endothelial cells of transgenic mice under transmission electron microscopy. RESULTS: The electrophoresis assay showed the expected 4 fragments of 0.9 kb, 1.1 kb, 1.2 kb and 4.2 kb in the Sma I digest and 2 fragments of 0.8 kb and 6.7 kb in Bgl II digest of plasmids pTie-1/hSR-A. The fragment sequence of tie-1 promoter and human SR-A cDNA in plasmids pTie-1/hSR-A was correct and no ATG before the translation initiation sites of human SR-A was found by sequence analysis. 561 injected and surviving embryos with the purified human SR-A minigene were implanted into the oviducts of 19 ICR pseudopregnant mice. Among the 54 surviving pups from 13 foster mothers, 7 were identified by PCR and Southern blot analysis. The results of RT-PCR and immunohistochemical analysis showed human SR-A was specifically expressed on vascular endothelial cells of the aorta and renal artery, as well as hepatic sinusoidal endothelial cells in transgenic mice. Transmission electron microscope (TEM) of aorta of transgenic mice showed that a large number of vesicles, multivesicle bodies and swollen mitochondria filled the plasma of endothelial cells. CONCLUSIONS: A transgenic mouse model with overexpression of human SR-A in endothelial cells was successfully established. The transgene was integrated and transmitted into the chromosome of transgenic mice. Tie-1 promoter controlled the transgene to express in endothelial cells in mice. Pinocytic activity of aortic endothelial cells in transgenic mice was higher than that of C57BL/6J mice. Our studies will provide a new transgenic model for investigation of atherosclerosis and functions of human SR-A.

Animals↗
PubMed2001

[Distribution of F13A01, FESFPS and vWA loci in ten minority populations in Yunnan of China].

The short tandem repeats (STR) is a kind of DNA sequence formed repeatedly and connectively subjected to a core unit of several base pairs. The non-interfered multi-PCR was applied with 3 loci in the same reaction system. By using the technique of denaturing polyacrylamide gel electrophoresis and silver stain, the allele frequencies distributions of 3 loci: F13A01, FESFPS and vWA in 10 minority populations only resided in Yunnan Province: Bai, Dai, Achang, Jingpo, Deang, Lahu, Bulang, Hani, Pumi and Jino. A satisfactory result was obtained and some significant genetic differences were noticed in different populations.

Antigens↗
PubMed2001

[The chemical decomposition of glutamine and its effect on hybridoma cell culture].

The chemical decomposition of glutamine is a first-order reaction. Its reaction constants under storage and culture conditions were determined as 0.0009 h-1 and 0.0032 h-1 respectively. Batch culture of hybridoma cell C50 with different initial contents of glutamine helped to understand its real metabolic characteristic. The results show that when the initial concentration of glutamine is lower than 5 mmol/L, more than 80% is used by cells. And the lower the initial content, the more being used. As the initial glutamine concentration increases, the ratio of its utilization decreases. When it reaches 10 nmol/L, the ratio decreases dramatically.

Ammonia↗
PubMed2001

Nasal carriage of Streptococcus pneumoniae among children in Beijing.

OBJECTIVE: To investigate the antimicrobial susceptibility of Streptococcus pneumoniae carried in the nose among children in Beijing and the distribution of serotypes, and to analyze the risk factors for nasal carriage of penicillin non-susceptible S. pneumoniae. METHODS: A disk diffusion test was applied to detect the antimicrobial susceptibilities of S. pneumoniae to erythromycin, trimethoprim-sulfamethoxazole, chloramphenicol and tetracycline. The E test was applied to determine the minimal inhibitory concentrations of penicillin, cefuroxime, cefotaxime, augmentin and imipenem. S. pneumoniae isolates were serotyped by the Quellung reaction. RESULTS: S. pneumoniae that was resistant to penicillin or cefuroxime was not found, but S. pneumoniae intermediate resistant to penicillin and cefuroxime accounted for 8.2% and 2.1%, respectively. All of the isolates were susceptible to cefotaxime, augmentin and imipenem. S. pneumonia that was resistant to erythromycin, trimethoprim-sulfamethoxazole and tetracycline were extremely numerous, accounting for 72%, 70% and 79%, respectively. Five serotypes (19, 6, 14, 23, 17) accounted for 54.7%, and nontypables accounted for 20.6% of all the S. pneumoniae. Previous history of otitis media was a risk factor we found for nasal carriage of penicillin non-susceptible S. pneumoniae. CONCLUSIONS: Continued surveillance of the antimicrobial susceptibilities of S. pneumoniae is necessary. A larger scale investigation is needed to identify if the 7 or 9-valent conjugate pneumococcal vaccine is appropriate for Chinese children.

Child, Preschool↗
PubMed2001

Prognostic value of dobutamine stress test in patients with septic shock.

AIM: To evaluate the prognostic effect of dobutamine stress test in patients with septic shock. METHODS: Patients with septic shock received intravenous infusion of dobutamine at 10 microg . kg-1 . min-1 for 1 h. Hemodynamics and oxygen metabolism was observed. A patient who was able to increase oxygen consumption index (VO2) by >15 % was designated as a responder to the test. RESULTS: In 47 patients with septic shock, twenty one responders and twenty six nonresponders were identified, and mortality was 33.3 % and 76.9 % respectively. After the dobutamine infusion, the responders showed increases in cardiac index (18.1 %), oxygen delivery index (12.7 %), VO2 (38.6 %), and oxygen extraction ratio (18.0 %), and reductions in systemic vascular resistance index (18.5 %). The nonresponders demonstrated increases in cardiac index (11.5 %), but no change in oxygen delivery, VO2, and oxygen extraction ratio. CONCLUSION: Dobutamine stress test might be a good predictor of outcome in patients with septic shock.

Aged↗
PubMed2001

[Effect of NPK and B supply levels on boron uptake and biological properties of different genotypic oilseed rape].

Pot experiment was conducted to study the boron absorption by oilseed rape(Brassica napus), the mechanism of its resistance to boron deficiency, and the effect of boron deficiency on its biological properties under different NPK supply levels. The results indicated that under boron deficiency, increasing NPK supply aggravated boron deficiency symptoms, which led to the decrease of leaf area and its growth rate and nitrate reductase activity(NRA) and the increase of chlorophyll(a + b) content at seedling stage, and the decrease of the number of productive branches and pods of each plant and seed yield at maturity. It was suggested that the ratio of boron concentration in youngest open leaves(YOL) to youngest mature leaves(YML) at seedling stage could be an index to judge the boron mobility in plants of different genotypic oilseed rape. Boron mobility and its utilization efficiency were one of the important nutritional mechanisms responsible for the difference in response of different genotypic oilseed rapes to boron deficiency.

Boron↗
PubMed2001

[Forest soil seed bank and natural regeneration].

The characteristics of temporal dynamics and spatial distribution of forest soil seed bank and their effects on natural regeneration were reviewed in this paper. The density of the seed bank of forest soil, which is affected by the types and ages of forest, is lower than that of cultivated land and grassplot, and can vary widely. The extent to which the composition of forest soil seed bank is influenced by its counterpart plantation depends on the stages of succession. The dynamics of forest soil seed bank is the combined effect of periodical and random factors. It is suggested that forest soil seed bank is the material base of forest regeneration, and the configuration and function of forest soil seed bank would influence the ability and the direction of natural forest regeneration. According to the characteristics of forest soil seed bank and obstructive factors influencing regeneration, some artificial measures can be adopted to accelerate natural regeneration. Studies on the forest soil seed bank should focus on the application of basic theories of disturbed ecology, and regard the reconstruction of degenerative ecosystem and the succession of populations in the ecotone as the main contents to study. As for the research method, it is advisable to employ long-term and located observations.

Regeneration↗
PubMed2001

[Detection of proteins and mRNA of p16, p53 and nm23 in mucoepidermoid carcinoma of salivary glands and their prognostic significance].

OBJECTIVE: To disclose the relationship between the expression of p16, p53 and nm23 and the significant morphologic characteristics in mucoepidermoid carcinoma. METHODS: The proteins and mRNA in paraffin blocks from 41 mucoepidermoid carcinoma patients were studied with immunohistochemical methods and in situ hybridization respectively. RESULTS: The negative expression of p16 was found in 62.5% (15/24) of the low differentiation grade and in 29.4% (5/17) of the high differentiation grade (P = 0.037). The positive p53 expression was detected in 70.8% (17/24) of the low grade neoplasms and in 23.5% (4/17) of the high grade (P = 0.003), while positive nm23 protein was present in 37.5% (9/24) and 64.7% (11/17) respectively (P = 0.086). However, no relationship was found between positive mRNA of p16, p53, nm23 and WHO pathologic grade. CONCLUSIONS: There is a significant correlation between expression of p16 and p53 and WHO pathologic grade of mucoepidermoid carcinoma, which indicates clinical prognostic significance. No correlation is noticed between the pathologic grade and the expression of nm23 protein and mRNAs of p16, p53 and nm23.

Adult↗
PubMed2001

[Distribution characteristics and seasonal dynamics of phosphorus and potassium in wetland ecosystem in the Sanjiang Plain].

From May to October in 1997, the plant, soil and logging water in the wetlands were sampled monthly, and their P and K concentrations were measured. With the method of one-factor non-linear regression analysis, the seasonal dynamics of P and K in two types of wetland i.e., in Carex lasiocarpa-Glyceria spiculosa wetland and in Deyeuxia angustifolia wetland were studied. The concentrations of P and K varied with different species of wetland plant and different organs of the same plant species. But their common property was that the concentration of K was higher than that of P, which shows that the mire-wetland plants had the property of enriching K element. The concentrations of P and K had an obvious seasonal dynamics in plant, soil and logging water, but the patterns were not the same. Some simulation models were obtained, which could be used to forecast the seasonal dynamics of P and K contents.

China↗
PubMed2001

[Effect of HCO3- on root growth and nutrient absorption of different rice genotypes].

Solution culture experiments with Zn-inefficient cultivar (IR26) and the Zn-efficient cultivar (IR8192-31-2) were conducted to study the effect of HCO3- on the root growth and nutrient absorption of different rice cultivars. The results showed that HCO3- strongly inhibited the root growth of Zn-inefficient cultivar especially at low Zn concentration. In contrast, that of Zn-efficient cultivar was slightly stimulated by HCO3- at low Zn concentration. HCO3- not only inhibited Zn absorption of Zn-inefficient cultivar, but also inhibited its absorption of Fe, Mn, Cu, implying that there was no specific inhibition of HCO3- on Zn absorption. These results demonstrated that the inhibition of root growth by HCO3- was likely to be the initial action of HCO3- in inducing Zn deficiency in lowland rice. With treatment of bicarbonate, Zn concentrations in upper and lower leaves of the Zn-efficient cultivar and their ratios were higher than those of the Zn-inefficient cultivar. The results showed that the Zn-efficient cultivar could transport more zinc from lower leaves to upper leaves, which might be-one of mechanisms that the Zn-efficient cultivar adapted to zinc deficiency in calcareous soil.

Absorption↗
PubMed2001

[Effect of boron fertilization on B uptake and utilization by oilseed rape(Brassica napus L.) under different soil moisture regimes].

Pot experiment was conducted in greenhouse to determine the effect of boron fertilization on B uptake and utilization by oilseed rape at seedling stage as influenced by soil moisture regime. The results showed that B concentration in shoot and root increased with the increase of soil water content and B fertilization level, while its utilization efficiency(BUE) and mobilization index(BMI) increased with the decrease of soil water content and B application level. Differences in BUE and BMI of test oilseed rape cultivars were significant, i.e., V1 showed higher BUE and BMI than V4 under the same conditions. It is concluded that BUE and B mobility in plant were the major factors responsible for the differences in response of different oilseed rape cultivars to B deficiency.

Absorption↗
PubMed2001

Prevention and treatment of hepatitis B relapse after liver transplantation.

OBJECTIVES: To investigate the effect of orthotopic liver transplantation (OLT) on hepatitis B(HB)-related diseases and the efficiency of prevention and treatment with lamivudine on recurrence of hepatitis B posttransplant in China. METHODS: Orthotopic liver transplantation (OLT) under veno-venous bypass was performed in 10, of whom 9 males had hepatitis B and 1 female had hepatocellular cancer (HCC) without HB pretransplant. Eight of the 9 males had fulminant hepatitis B (FHB) and they all had preoperative serious jaundice, ascites and coagulopathy. Six had encephalopathy; 1 was associated with acute renal failure, and 1 with gastrointestinal hemorrhage. Seven of the 10 patients had lamivudine to prevent reinfection with hepatitis B. RESULTS: Of the 8 patients who have survived for 2-12 months, 7 have survived for 6-12 months. Two died, one of recurrent FHB and the other from multi-organ failure (MOF). Seven preoprative HB patients of the 8 survivors have excellent liver function through 1 has positive HBsAg 6 months after OLT. One of the 8 survivors, the female with HCC pretransplant, suffered hepatitis B 6 months after OLT and her hepatic function has been gradually improving with lamivudine therapy. CONCLUSIONS: OLT is an effective therapy for certain cases of FHB and HCC and lamivudine may prevent recurrence of hepatitis B after OLT.

Adult↗
PubMed2001

Retinoic acid regulated insulin-like growth factor gene expression in cord blood lymphocytes.

OBJECTIVE: To explore the immune promotion mechanism of retinoic acid (RA). METHODS: Reverse Transcription-Polymerase chain reaction (RT-PCR) was used to detect the gene expression of insulin like growth factor I (IGF-I) and IGF receptors (IGF-IR and IGF-IIR) in vitro, and their regulation by RA in human cord blood lymphocyte (CBL). RESULTS: Significant upregulation of IGF-I, IGF-IR and IGF-IIR mRNA was found at 6-24 hours in CBL incubated with physiologic concentrations of RA as compared to those without RA. CONCLUSION: The enhancement of IGF expression may be an important pathway for vitamin A to promote immune cellular functions.

Cells, Cultured↗
PubMed2001

Autologous peripheral blood stem cell transplantation in the patients with hematologic malignancies and solid tumors.

OBJECTIVE: To evaluate the long-term therapeutic effects of autologous peripheral blood stem cell transplantation (auto-PBSCT) on the treatment of hematological and solid tumors. METHODS: Fifty-one patients were recruited in this auto-PBSCT study, in which several potentially important parameters were studied including the optimal time for stem cell collection, the dose of stem cell reinfusion, the time of hematopoietic reconstitution, the disease free survival (DFS) and overall survival (OS), complications related to transplantation, and maintenance chemotherapy after auto-PBSCT. RESULTS: After APBSCT, 3-year and 5-year survival rates of NHL were 83.3%; those of AML were 74.7%; those of MM were 37.9% and 19%; those of ALL were 40% and 0% respectively. Hematopoietic reconstitution was greatly promoted by granulocyte colony stimulating factor (G-CSF). The mean time for patients' neutrophil to recover up to > 0.5 x 10(9)/L after APBSCT was 11.14 days in the group of the patients receiving G-CSF in contrast to 17.6 days in the group receiving no G-CSF. The most common complications of transplantation were fever, liver dysfunction and hypokalaemia, which were curable. No death was due to transplantation related complications. CONCLUSION: Comparing with conventional chemotherapy, our study suggests that auto-PBSCT is a very important therapeutic option that can significantly improve the prognosis in the patients with hematological and solid tumors, especially in the patients with AML and NHL.

Adolescent↗