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Biomedical subjects

Bin Yang

Publications and source records attributed to Bin Yang.

At least 73 records · Page 4Linked to original sources
PubMed2005

[Development of the study on germplasm resources of medicinal plants: construction of core collection].

According to the successful experience of studying on crops, this paper introduced the conception of the core collection of medicinal plants, and analyzed the characteristic and the way to construct it. Studies on the core collection would fulfill the management and utilize the germplasm resources conveniently and provide a new idea and a method to study on the germplasm resources of medicinal plants. It is necessary to study on the core collection for the development of the germplasm resources of medicinal plants.

Chromatography, High Pressure Liquid↗
PubMed2004

A DEAD box protein facilitates HIV-1 replication as a cellular co-factor of Rev.

HIV-1 Rev escorts unspliced viral mRNAs out of the nucleus of infected cells, which allows formation of infectious HIV-1 virions. We have identified a putative DEAD box (Asp-Glu-Ala-Asp) RNA helicase, DDX1, as a cellular co-factor of Rev, through yeast and mammalian two-hybrid systems using the N-terminal motif of Rev as "bait". DDX1 is not a functional homolog of HIV-1 Rev, but down-regulation of DDX1 resulted in an alternative splicing pattern of Rev-responsive element (RRE)-containing mRNA, and attenuation of Gag p24 antigen production from HLfb rev- cells rescued by exogenous Rev. Co-transfection of a DDX1 expression vector with HIV-1 significantly increased viral production. DDX1 binding to Rev, as well as to the RRE, strongly suggest that DDX1 affects Rev function through the Rev-RRE axis. Moreover, down-regulation of DDX1 altered the steady state subcellular distribution of Rev, from nuclear/nucleolar to cytoplasmic dominance. These findings indicate that DDX1 is a critical cellular co-factor for Rev function, which maintains the proper subcellular distribution of this lentiviral regulatory protein. Therefore, alterations in DDX1-Rev interactions could induce HIV-1 persistence and targeting DDX1 may lead to rationally designed and novel anti-HIV-1 strategies and therapeutics.

Animals↗
PubMed2004

Protective effects of recombinant human growth hormone on cirrhotic rats.

AIM: To investigate the effects and molecular mechanisms of recombinant human growth hormone (rhGH) on protecting liver function and alleviating portal hypertension of liver cirrhotic rats. METHODS: Liver cirrhosis of male Sprague-Dawley rats was induced by administration of thioacetamide. The rats with or without liver cirrhosis were randomly divided into four groups. Group A consisted of the normal rats was treated with normal saline (NS), group B consisted of the normal rats was treated with rhGH, group C consisted of cirrhotic rats was treated with NS, and group D consisted of cirrhotic rats was treated with rhGH. The rats of different groups were subcutaneously injected with 0.5 mL of NS or 333 ng/kg of rhGH daily for 7 d. After treatments, the following parameters were examined, including GH-binding capacity (R(T)) by (125)I-hGH binding, growth hormone receptor mRNA(GHR mRNA) expression by RT-PCR, relative content of collagen (RCC) by histomorphomertry, and level of malon-dialdehyde (MDA) and superoxide dismutase (SOD) in liver tissue by thiobarbituric acid reaction and pyrogallic acid self-oxidation, respectively. Serum albumin (ALB), alanine transaminase (ALT) and portal vein pressure (PVP) were also examined. RESULTS: rhGH up-regulated both the GH-binding capacity (R(T)) and the expression of GHR mRNA in vivo. R(T) in group A (72+/-12 fmol/mg protein) was significantly higher than that in group C (31+/-4 fmol/mg protein) (P<0.05). R(T) in group B (80+/-9 fmol/mg protein) increased markedly compared to group A (P<0.05). R(T) in group D (40+/-7 fmol/mg protein) raised remarkably compared with group C (P<0.05), but less than that in group A, and there was no significant GH binding affinity contrast (Kd) change. The GHR mRNA level (iOD, pixel) in group A (29+/-3) was significantly higher than that in group C (23+/-3) (P<0.05). GHR mRNA levels were significantly raised in group B (56+/-4) and group D (42+/-8) compared with groups A and C (29+/-3 and 23+/-3, respectively) (P<0.05). Compared with the normal liver, MDA level was higher and SOD level was lower in cirrhotic livers. After rhGH treatment, MDA level was significantly declined to 12.0+/-2.2 nmol/mg protein and SOD was raised to 1 029+/-76 U/mg protein in group D (P<0.05). ALB levels in groups B and D (42+/-7 g/L and 37+/-7 g/L, respectively) were significantly raised compared with those in groups A and C (35+/-5 g/L and 29+/-4 g/L, respectively) (P<0.05). ALT level was markedly lower in group D (69+/-7 U/L) compared to group C (89+/-15 U/L) (P<0.05), and close to group A (61+/-10 U/L). RCC in group C (22.30+/-3.86%) was significantly higher than that in group A (1.14+/-0.21%) and group D (14.70+/-2.07%) (P<0.05). In addition, rhGH markedly alleviated portal hypertension in liver cirrhotic rats (group D vs C, 9.3+/-1.5 cmH(2)O vs 14.4+/-2.0 cmH(2)O) (P<0.05). CONCLUSION: Pharmacological doses of rhGH can increase R(T) and GHR mRNA expression, ameliorate liver functions, repress fibrosis and decline portal hypertension, suggesting it has potentially clinical usage as a hepatotropic factor.

Animals↗
PubMed2004

Effect of xylan and lignin removal by batch and flowthrough pretreatment on the enzymatic digestibility of corn stover cellulose.

Compared with batch systems, flowthrough and countercurrent reactors have important potential advantages for pretreating cellulosic biomass, including higher hemicellulose sugar yields, enhanced cellulose digestibility, and reduced chemical additions. Unfortunately, they suffer from high water and energy use. To better understand these trade-offs, comparative data are reported on xylan and lignin removal and enzymatic digestibility of cellulose for corn stover pretreated in batch and flowthrough reactors over a range of flow rates between 160 degrees and 220 degrees C, with water only and also with 0.1 wt% sulfuric acid. Increasing flow with just water enhanced the xylan dissolution rate, more than doubled total lignin removal, and increased cellulose digestibility. Furthermore, adding dilute sulfuric acid increased the rate of xylan removal for both batch and flowthrough systems. Interestingly, adding acid also increased the lignin removal rate with flow, but less lignin was left in solution when acid was added in batch. Although the enzymatic hydrolysis of pretreated cellulose was related to xylan removal, as others have shown, the digestibility was much better for flowthrough compared with batch systems, for the same degree of xylan removal. Cellulose digestibility for flowthrough reactors was related to lignin removal as well. These results suggest that altering lignin also affects the enzymatic digestibility of corn stover.

Bioreactors↗
PubMed2004

Wavelength dependence of liquid-vapor interfacial tension of Ga.

The wave-vector dependence of the liquid-vapor interfacial tension of Ga, gamma(q), has been determined from diffuse x-ray scattering measurements. The ratio gamma(q)/gamma(0)=1 for q<0.05 A(-1) decreases to 0.5 near q=0.22 A(-1), and increases strongly for larger q. The observed form for gamma(q)/gamma(0) is consistent with the prediction from the Mecke-Dietrich theory when the known stratified liquid-vapor interfacial density profile of Ga and a pseudopotential based pair interaction with appropriate asymptotic (r--> infinity ) behavior are used. The detailed behavior of gamma(q)/gamma(0) depends on the particular forms of both the interfacial density profile and the asymptotic falloff of the atomic pair interaction.

Journal Article↗
PubMed2004

Synthesis and helical structure of lactam bridged BH3 peptides derived from pro-apoptotic Bcl-2 family proteins.

Protein-protein interactions within the Bcl-2 family are mediated by the helical BH3 domains of pro-apoptotic family members. To study the mechanism of this BH3 domain-protein interaction, a series of cyclic lactam bridged BH3 peptide analogues were synthesized by a novel combined Fmoc/tBu/Bzl protections strategy. These peptide analogues were studied by circular dichroism spectroscopy and found to adopt highly helical structure. These helical peptides stabilized by a lactam bridge serve as useful models to analyze the structure-function relationship of the pro-apoptotic BH3 domains. Furthermore, the synthetic method for lactam bridge incorporation reported here may find application in studies of other helical structures and development of helix mimics.

Amino Acid Sequence↗
PubMed2004

Epigenetic inactivation of SFRP genes allows constitutive WNT signaling in colorectal cancer.

Aberrant WNT pathway signaling is an early progression event in 90% of colorectal cancers. It occurs through mutations mainly of APC and less often of CTNNB1 (encoding beta-catenin) or AXIN2 (encoding axin-2, also known as conductin). These mutations allow ligand-independent WNT signaling that culminates in abnormal accumulation of free beta-catenin in the nucleus. We previously identified frequent promoter hypermethylation and gene silencing of the genes encoding secreted frizzled-related proteins (SFRPs) in colorectal cancer. SFRPs possess a domain similar to one in the WNT-receptor frizzled proteins and can inhibit WNT receptor binding to downregulate pathway signaling during development. Here we show that restoration of SFRP function in colorectal cancer cells attenuates WNT signaling even in the presence of downstream mutations. We also show that the epigenetic loss of SFRP function occurs early in colorectal cancer progression and may thus provide constitutive WNT signaling that is required to complement downstream mutations in the evolution of colorectal cancer.

Cell Line, Tumor↗
PubMed2004

Local strain-mediated chemical potential control of quantum dot self-organization in heteroepitaxy.

From observations of self-assembly of Ge quantum dots directed by substrate morphology, we propose the concept of control of ordering in heteroepitaxy by a local strain-mediated surface chemical potential. Using quite simple lithography, we demonstrate directed quantum dot ordering. The strain part of the chemical potential is caused by the spatially nonuniform relaxation of the strained layer, which in our study is the Ge wetting layer, but, more generally, can be a deposited strained buffer layer. This model provides a consistent picture of prior literature.

Journal Article↗
PubMed2004

Particle disease: cytopathologic findings of an unusual case.

Particle disease is a rare lesion that results from an inflammatory response due to wear debris-induced osteolysis following arthroplasty. Particles resulting from the wear debris cause macrophage activation and phagocytosis. Particle disease often leads to joint loosening and implant failure. Radiologically, it often results in a well-defined osteolytic lesion-mimicking tumor. A 68-year-old man who presented with chronic hip pain following total hip replacement was studied by fine-needle aspiration. An ultrasound-guided aspiration revealed hypercellular smears consisting predominantly of proliferating mesenchymal cells, foamy macrophages, inflammatory cells, and background acellular debris. Numerous multinucleated giant cells were observed as well. Differential diagnosis includes primary or metastatic clear-cell tumors.

Aged↗
PubMed2004

Group-selective immunoassay for the detection of morphine in urine.

A new competitive inhibition immunoassay (group-selective immunoassay; GSI) has been developed to detect free morphine in urine with the Fab' fragments of monoclonal antibodies (MAbs) (1B(12)F(9)B(4), IgG(1), kappa, K(aff) = 9.66 x 10(10)M(-1)). At the first assay step, microtiter plates were coated with morphine-ovalbumin (M-6-S-OVA), in which free amino acids were protected by a glutaraldehyde cross-linking modification. The modification did not essentially influence the antibody-binding capacity of the immunosorbent. At the second assay step, anti-morphine MAbs' Fab' fragments, in which free amino groups were biotinylated by N-hydrosuccinimide-biotin ester, were bound to chemically modified immunosorbent. The biotin residues were then detected by the streptavidin-peroxide conjugate. This method has a sensitivity of 3.50 x 10(-15) mol/L using very little volume of sample, covering up to almost 1.20 x 10(-11) mol/L of standard concentration of morphine with good reproducibility. Standard curve prepared in urine indicated a good correlation between the concentration of morphine and the value of OD (y = 1/ax + b; r = 0.99939257, S = 0.01138127). Coefficients of variation for this immunoassay were 1.41 approximately 6.61% within-a-day assay and 2.31 approximately 8.99% between days assay. The recoveries were 94 approximately 101.4% from negative urine and 95.2 approximately 107.5% from positive urine samples, respectively. This method has application as a specific screen for morphine in drug abusers, to study the metabolism of the drug in the body, or to screen the monoclonal antibodies (MAbs) against morphine.

Enzyme-Linked Immunosorbent Assay↗
PubMed2004

Inhibitors directed towards caspase-1 and -3 are less effective than pan caspase inhibition in preventing renal proximal tubular cell apoptosis.

BACKGROUND: Uncontrolled apoptosis contributes to tubular cell deletion in renal scarring. Caspase-3 has a central role in the execution of apoptosis and may provide a target for regulating cell death. Here we evaluate three caspase inhibitors: B-D-FMK (pan caspase inhibitor), Z-DEVDFMK (predominantly Caspase-3 inhibitor) and Z-VAD-FMK (predominantly Caspase-1 and -3 inhibitor) to ameliorate apoptosis induced by cisplatin in rat proximal tubular (RPT) cells. METHODS: Caspase-3 activity (substrate cleavage assay) and protein (immunocytochemistry and Western blotting), apoptosis (Annexin V flow cytometry, in situend labelling of fragmented DNA, light/electron microscopy and DNA laddering) and cell survival (trypan blue exclusion and propidium iodide flow cytometry) were determined in RPT cells exposed to cisplatin with and without caspase inhibitors. RESULTS: Cisplatin induced a dose-dependent increase in Caspase-3 activity and 8-fold of increase in apoptosis (p < 0.01) when applied for 24 h at 100 microM. B-D-FMK (40 microM), Z-DEVD-FMK (15 microM) and Z-VAD-FMK (22 microM) almost completely inhibited the 25-fold increase in Caspase-3 activity and decreased apoptosis from 15.9 +/- 4.4 to 2.0 +/- 0.6% (p < 0.01), 15.0 +/- 2.2 and 15.0 +/- 2.2% respectively. DNA ladders were visible in cisplatin-treated cells, which disappeared following addition of B-D-FMK and decreased with Z-VAD-FMK and Z-DEVD-FMK. Cisplatin reduced cell survival to 61% by trypan blue exclusion. B-D-FMK and Z-VAD-FMK increased this to 87 and 75%, but Z-DEVD-FMK had no significant effect. CONCLUSIONS: Cisplatin causes an increase in RPT apoptosis that is associated with increased Caspase-3 activity. All caspase inhibitors were equally effective at reducing Caspase-3 activity, however the pan caspase inhibitor B-D-FMK was more effective at preventing apoptosis and increasing cell survival. Therefore, pan caspase inhibition offers the greatest potential for the prevention of renal tubular cell deletion by uncontrolled apoptosis.

Amino Acid Chloromethyl Ketones↗
PubMed2004

[Wavefront-guided laser in situ keratomileusis for myopia].

OBJECTIVE: To compare the clinical results of wavefront-guided versus conventional LASIK surgery in the treatment of myopia. METHODS: One hundred and thirteen eyes underwent wavefront-guided LASIK (Zyoptix) and 335 eyes were received conventional LASIK surgery (Planoscan). Besides visual acuity and refractions, the higher order aberrations and contrast sensitivity are also compared after surgery. RESULTS: The postoperative refractions were not significantly different between the Zyoptix group and Planoscan group. 33.6% of Zyoptix patient and 17.0% of Planoscan patient respectively, had postoperative uncorrected visual acuity than their preoperative best corrected visual acuity. At 6 mm pupil size, the higher order RMS was increased by 100% in the Planoscan group, while in the Zyoptix group, it was increased only by 35% postoperatively. Six months after operation, the contrast sensitivity of Planoscan patients returned to their preoperative baseline. However, the Zyoptix patients had slightly better contrast sensitivity than their preoperative level. CONCLUSION: Patients undergoing Zyoptix treatment have better quality of vision after surgery than Planoscan patients.

Adult↗
PubMed2004

[Change of corneal thickness after laser in situ keratomileusis].

OBJECTIVE: The corneal thickness was measured in and after in situ keratomileusis (LASIK) to investigate the accurate ablation depth on cornea during the operation and the possible mechanism of myopic after operation. METHODS: From August 1999 to June 2000, 650 myopia patients were treated by LASIK. The changes in cornea thickness were measured before, during and 1 week, 1, 3, 6 and 12 month after the surgery. RESULTS: By the measurement of cornea thickness during the operation, the real cornea ablated thickness was (32.15 +/- 7.23) micro m different from the expected value. Central thickness of the cornea and the refraction could be stable in six months after the operation. CONCLUSIONS: The cornea thickness and the refraction would be stable in six months after the operation. Age of the patients is the key factor that influences the stability of ocular refraction.

Age Factors↗
PubMed2004

[Association of T cell subsets with clinical status and hepatic pathology in children with chronic hepatitis B virus infection].

BACKGROUND: To study characteristics of peripheral T cell subsets in 94 children with chronic hepatitis B and to elucidate its relationships with clinical status and hepatic pathology. METHODS: Peripheral T cell subsets were detected using flow cytometric analysis with specific monoclonal antibodies staining in 94 patients with HBV infection. The authors simultaneously detected their serum ALT, markers of HBV infection and examined liver biopsy material for pathological changes. RESULTS: In patients with serious liver lesion, the ratio of CD4+/CD8+ cells was significantly higher than those with mild lesion (1.41+/-0.54 vs 1.08+/-0.35, P less than 0.05), which seemed to be associated with the various liver lesions among the patients. In female cases, the levels of CD4+ T cells and the ratio of CD4+/CD8+ T cells were higher than their counterpart in male cases (33.1+/-5.39 vs 28.8+/-6.28, 1.28+/-0.32 vs 1.02+/-0.36, P less than 0.05), but the level of CD8+ T cells was lower than those in males (26.79+/-4.66 vs 30.51+/-7.17, P less than 0.05). There was no obvious correlation between T cell subsets and circulating HBV viral load, the size of spleen among the HBV-infected children. CONCLUSION: The characteristics of peripheral T cell subsets probably suggests the immune disorder occurred in these children with hepatitis B compared with healthy controls and its mechanism needs further investigation.

Child↗
PubMed2004

[Diagnosis of tubular ectasia of the rete testis with color flow Doppler imaging].

OBJECTIVE: To diagnose tubular ectasia of the rete testis with color flow Doppler imaging. METHODS: Sonographic, CDFI and pulse wave Doppler appearance in tubular ectasia of the rete testis was described. RESULTS: The characteristic ultrasound appearance with no associated soft-tissue abnormality and no flow on color flow Doppler imaging was seen. CONCLUSION: Color Doppler ultrasound imaging is the first choice for the diagnosis of tubular ectasia of the rete testis.

Aged↗
PubMed2004

[Changes in level of organic acids in fructus crataegi after processing].

OBJECTIVE: To compare and analyze the organic acids level in fruit of Crataegus pinnatifida var. major before and after processing. METHOD: The amount of total organic acids and individual citric acid, malate acid, ursolic acid and oleanolic acid in fruit of C. pinnatifida var. major before and after processing were determined by pH titration and HPLC analysis. RESULT: Good linear relationship between peakarea and amount was noted for 0.28-9.02 microg of malate acid, with a correlation coefficient of 0.9998. Regression equation was Y = 2344.7 + 49309.6 X. Good linear relationships between the logarithm of peak area and amount were noted for 0.348-1.74 microg of usolic acid and 0.498-2.48 microg of oleanolic acid, with a correlation coefficient of 0.9998 in each case. Regression equations were Y = 1.3628 X + 5.9508 and Y = 1.4447 X + 5.8236, respectively. CONCLUSION: The lipid-soluble organic acids mostly remain whereas only about 70% of the water-soluble acids remain after processing in fruit of C. pinnatifida var. major.

Citric Acid↗
PubMed2004

[Studies on processing of Fructus Crataegi].

Not only the evolution of the processing of Fructus Crataegi, but also the difference of chemical consitituents, pharmacological effects and clinical application before and after the processing are reviewed, based on 26 references of literature. A way to further study the processing of Fructus Crataegi is provided.

Antidiarrheals↗