Biomedical subjects

Yu Yao

Publications and source records attributed to Yu Yao.

15 recordsLinked to original sources

PubMed2006

Protective activities of Vaccinium antioxidants with potential relevance to mitochondrial dysfunction and neurotoxicity.

Both the neurotransmitter dopamine (DA) and a neurotoxic metabolite, 6-hydroxy DA, can be oxidized to generate hydrogen peroxide and other reactive species (ROS). ROS promote oxidative stress and have been implicated in dopaminergic neurodegeneration, e.g., Parkinson's disease (PD). There is also evidence for a relation between catecholamine-mediated oxidative damage in dopaminergic neurons and the effects of these neurotransmitters on the redox state of cytochrome c (Cytc). In neurons and other cells, oxidative stress may be enhanced by abnormal release of Cytc and other mitochondrial proteins into the cytoplasm. Cytc release can result in apoptosis; but sub-apoptogenic-threshold release can also occur, and may be highly damaging in the presence of DA metabolites. Loss of mitochondrial membrane integrity, a pathological situation of relevance to several aging-related neurodegenerative disorders including PD, contributes to release of Cytc; and the level of such release is known to be indicative of the extent of mitochondrial dysfunction. In this context, we have used a Cytc-enhanced 6-hydroxy DA oxidation reaction to gauge dietary antioxidant activities. Anthocyanin-rich preparations of Vaccinium species (Vaccinium myrtillus, Vaccinium corymbosum, and Vaccinium oxycoccus) as well as a purified glycosylated anthocyanidin were compared. The most potent inhibition of oxidation was observed with V. myrtillus preparation: 50% inhibition with 7 microM of total anthocyanins. This activity was 1.5-4 times higher than that for the other preparations or for the purified anthocyanin. Ascorbate (Vitamin C), at up to 4-fold higher concentrations, did not result in significant inhibition in this assay. Antioxidant activity in the assay correlated strongly (r2>0.91, P<0.01) with reported Vaccinium content of anthocyanins and total cyanidins, but not quercetin or myricetin. The results provide evidence for the high potency of anthocyanins towards a potentially neurotoxic reaction, and provide a basis for in vivo testing of these flavonoids and their physiological metabolites in the context of neuro- and mitochondrio-protective effects.

Animals↗

PubMed2006

Development of an immunocytokine, IL-2-183B2scFv, for targeted immunotherapy of ovarian cancer.

OBJECTIVES: The purpose of this study was to develop an immunocytokine for immunotherapy of human ovarian cancer. METHODS: The single-chain Fv of a monoclonal antibody, COC183B2, specific for an ovarian carcinoma-associated antigen (OC183B2), was genetically fused with the coding sequence of interleukin 2 (IL-2). The fusion protein, also called immunocytokine, IL-2-183B2scFv, was expressed in CHO cells and examined for its specificity and biological function. RESULTS: The immunocytokine, IL-2-183B2scFv, retained the functions of both the antibody and IL-2. It was able to target IL-2 to tumor cells that overexpress OC183B2, and stimulate the proliferation of an IL-2-dependent cell line, CTLL-2. CONCLUSIONS: The IL-2-183B2scFv maintains the functions of both IL-2 and antibody. It can be potentially used for immunotherapy of ovarian cancer by delivering a high concentration of IL-2 to OC183B2-expressing ovarian cancer cells.

Animals↗

PubMed2006

High-performance, high-chip-count optical code division multiple access encoders-decoders based on a reconstruction equivalent-chirp technique.

Fiber Bragg grating-based, 511 chip, 500 Gchip/s encoders-decoders are experimentally demonstrated by the reconstruction equivalent-chirp (REC) method. Encoding-decoding efficiency close to the theoretical value is achieved. Without any real phase shifts, the encoders-decoders are fabricated by use of the traditional setup. Highly precise phase control requires only submicrometer precision. The encoding-decoding performance can be further improved by REC-based correction.

Journal Article↗

PubMed2006

Detecting single quantum dot motion with nanometer resolution for applications in cell biology.

Quantum dots (QDs), semiconductor particles of nanometer dimension, have emerged as excellent fluorescent analogs in tracer experiments with single molecule sensitivity for bioassays. Cell imaging greatly benefits from the remarkable optical and physical properties of these inorganic nanocrystals: QDs are much brighter and exhibit a higher resistance to photobleaching than traditional fluorophores, and their narrow emission spectrum and flexible surface chemistry make them particularly suitable for multiplex imaging. Here, we have demonstrated the achievement of a nanometer spatial resolution on the position of a single QD in a simple optomechanical instrument using a high-sensitivity low-noise detector, an intensified CCD camera. Furthermore, nanometer variations in the amplitude of a QD's sinusoidal oscillations could be quantitatively distinguished after fast Fourier transform (FFT) based data processing. As confirmed by experiments where QDs were attached to the surface of bovine aortic endothelial cells, this method can be exploited in biology to assess molecular and subcellular contributions to responses such as motility, intracellular trafficking, and mechanotransduction, with high resolution and minimal disturbance to cells.

Animals↗

PubMed2006

[Research on resveratrol's mechanism of immunity in anti-aging].

OBJECTIVE: To research resveratrol's mechanism of immunity in anti-aging and explore the new clinical use of resveratrol. METHODS: The sub acute aging model was made by continuous subcutaneous injection of D galactose to mice inducing reactive oxygen species (ROS). Meanwhile, the resveratrol was given and its effect on anti-aging was observed. RESULTS: The resveratrol could increase the content of SOD and decrease the content of MDA in serum. There was no change in spleen index, but thymus index increased obvionsly. There was no change in the quantity of CD4+, but the quantity of CD8+ increased and the ratio of CD4+/CD8+ was decreased. The serum IL-6 and IL-8 level were decreased obviously. CONCLUSION: The resveratrol possessed the function to anti-aging and the applications foreground in anyi-aging.

Aging↗

PubMed2005

Is decompressive craniectomy for malignant middle cerebral artery territory infarction of any benefit for elderly patients?

BACKGROUND: Malignant middle cerebral artery (MCA) infarction is characterized by mortality rate of up to 80%. The aim of this study was to determine the value of decompressive craniectomy in patients who present with malignant MCA territory infarction and to compare functional outcome in elderly patients with younger patients. METHODS: Patients with malignant MCA territory infarction treated in our hospital between January 1997 and March 2003 were included in this retrospective analysis. The National Institutes of Health Stroke Scale (NIHSS) assessed neurologic status at admission, operation, and at 1 week after surgery. All patients were followed up for assessment of functional outcome by the Barthel Index (BI) and the modified Rankin Scale (RS) at 3 to 9 months after infarction. RESULTS: Twenty-five patients underwent decompressive craniectomy. The mortality was 7.7% in younger patients (ages <60 years) compared with 33.3% in elderly patients (ages >/=60 years) (P > .05). All patients had significant decrease of NIHSS after surgery (P < .001). At follow-up, younger patients who received surgery had significantly better outcome with mean BI of 75.42 and Rankin score of 3.00; however, none of the elderly survivors had a BI score above 60 or a Rankin score below 4. CONCLUSION: Decompressive craniectomy in younger patients with malignant MCA territory infarction improves both survival rates and functional outcomes. Although survival rates were improved after surgery in elderly patients, functional outcome and level of independence were poor.

Age Factors↗

PubMed2005

Is decompressive craniectomy for malignant middle cerebral artery infarction of any worth?

OBJECTIVE: Malignant middle cerebral artery (MCA) infarction is characterized by mortality rate of up to 80%. The aim of this study was to determine the value of decompressive craniectomy in patients presenting malignant MCA infarction compared with those receiving medical treatment alone. METHODS: Patients with malignant MCA infarction treated in our hospital between January 1996 and March 2004 were included in this retrospective analysis. The National Institute of Health Stroke Scale (NIHSS) was used to assess neurological status on admission and at one week after surgery. All patients were followed up for assessment of functional outcome by the Barthel index (BI) and modified Rankin Scale (RS) at 3 months after infarction. RESULTS: Ten out of 24 patients underwent decompressive craniectomy. The mean interval between stroke onset and surgery was 62.10 h. The mortality was 10.0% compared with 64.2% in patients who received medical treatment alone (P<0.001). The mean NIHSS score before surgery was 26.0 and 15.4 after surgery (P<0.001). At follow up, patients who underwent surgery had significantly better outcome with mean BI of 53.3, RS of 3.3 as compared to only 16.0 and 4.60 in medically treated patients. Speech function also improved in patients with dominant hemispherical infarction. CONCLUSION: Decompressive craniectomy in patients with malignant MCA infarction improves both survival rates and functional outcomes compared with medical treatment alone. A randomized controlled trial is required to substantiate those findings.

Adult↗

PubMed2005

[Purification and characterization of corresponding antigen recognized by monoclonal antibody 183B2 against ovarian carcinoma].

OBJECTIVE: To purify MAb183B2 corresponding antigen of ovarian carcinomas and study its physical and chemical characteristics. METHODS: The strongest positive samples reacted with MAb183B2 were screened from ovarian cancer ascites with indirect enzyme linked immunosorbent assay (ELISA). Then the antigen was purified from ascitic fluid by affinity chromatography with MAb183B2. Nature of the purified antigen was examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and western blot and its reactivity was determined after treatment with NaIO4, trypsin, pronase, neuraminidase, deglycolipid mixture and heating. Two dimensional electrophoresis combined with western blot was then used to isolate and identify the antigen from ovarian cancer cell line SKOV3. RESULTS: The reactivity of the antigen after treated by NaIO4, neuraminidase and deglycolipid mixture was still positive, while it was negative after treated by trypsin, pronase and heating. The antigen proved to be composed of two different subunits of 56,000 and 25,000 by SDS-PAGE, and MAb183B2 could blot the 56,000 band by western blot. The antigen from the SKOV3 cell line displayed microheterogeneity appearing as three spots over a pI range 5.3 approximately 5.8 at 56,000. CONCLUSIONS: The epitope of 183B2-antigen is at its peptide core. The antigen belongs to the Ig super family and might be a new ovarian carcinoma associated antigen.

Antibodies, Monoclonal↗

PubMed2004

Global regulation of erythroid gene expression by transcription factor GATA-1.

Transcription factor GATA-1 is required for erythropoiesis, yet its full actions are unknown. We performed transcriptome analysis of G1E-ER4 cells, a GATA-1-null erythroblast line that undergoes synchronous erythroid maturation when GATA-1 activity is restored. We interrogated more than 9000 transcripts at 6 time points representing the transition from late burst forming unit-erythroid (BFU-E) to basophilic erythroblast stages. Our findings illuminate several new aspects of GATA-1 function. First, the large number of genes responding quickly to restoration of GATA-1 extends the repertoire of its potential targets. Second, many transcripts were rapidly down-regulated, highlighting the importance of GATA-1 in gene repression. Third, up-regulation of some known GATA-1 targets was delayed, suggesting that auxiliary factors are required. For example, induction of the direct GATA-1 target gene beta major globin was late and, surprisingly, required new protein synthesis. In contrast, the gene encoding Fog1, which cooperates with GATA-1 in beta globin transcription, was rapidly induced independently of protein synthesis. Guided by bioinformatic analysis, we demonstrated that selected regions of the Fog1 gene exhibit enhancer activity and in vivo occupancy by GATA-1. These findings define a regulatory loop for beta globin expression and, more generally, demonstrate how transcriptome analysis can be used to generate testable hypotheses regarding transcriptional networks.

Animals↗

PubMed2004

A cytochrome c-enhanced peroxidation reaction with potential use in screening dietary antioxidants.

Reactive oxygen species (ROS) that result from events such as cellular respiration can cause damage to biological molecules and tissues. A variety of endogenous and dietary antioxidants function in moderating the extent of oxidative damage in the body. In this report, a pro-oxidant system is presented as an assay for screening possible antioxidant activities of dietary factors. The assay reaction involves peroxidatic oxidation of the redox indicator N,N,N',N'-tetramethyl-1,4-phenylenediamine (TMPD). It is shown that the reaction rate is enhanced by up to 10-fold in the presence of cytochrome c (cyt c), a mitochondrial electron transport protein. The extent to which selected dietary antioxidant factors inhibit the cytochrome c-enhanced peroxidatic oxidation of TMPD is also reported. Considering the known pathological consequences of mitochondrial membrane disruption and cytochrome c release in the cell, this reaction and assay may be of pathological and therapeutic relevance.

Antioxidants↗

PubMed2004

Polyelectrolyte-stabilized glucose biosensor based on woodceramics as electrode.

OBJECTIVE: Different biosensors for early diagnosis of diabetes have been discussed increasingly. We demonstrate the applicability of a glucose biosensor for rapid and quantitative determination of glucose in experimental sample solutions. DESIGN AND METHODS: Polyethylenimine (PEI)-stabilized glucose oxidase (GOD) was used for the construction of stable glucose biosensor utilizing a simple manufacture procedure. The stabilized glucose oxidase was immobilized by physical adsorption into activated porous and conductive carbonaceous material-woodceramics that served as the immobilization matrix and the electrochemical transducer. The optimum parameters for the construction of the biosensor and the influences of pH and temperature on the biosensor response were explored. RESULTS: Optimum results were obtained using soaking solutions of 2300 U/ml GOD, 10 mg/ml mediator toluidine blue O (TBO), and 2.0%, w/v PEI. The sensitivity of the resulting biosensor for glucose was 1.22 microA/mM, with a linear response in the concentration range of 0.5-7 mM. The sensor-to-sensor reproducibility was good, the relative standard deviation (R.S.D.) being less than 8.0%. The storage and operational stabilities of the glucose biosensor were good. CONCLUSIONS: The glucose biosensor provides reproducible and quantitative information on glucose within minutes and is applicable for the detection of glucose in experimental samples.

Aspergillus niger↗

PubMed2004

[Human pituitary tumor transforming gene 1 expression in ovarian carcinoma and its clinical significance].

BACKGROUND & OBJECTIVE: Human pituitary tumor transforming gene 1 (hPTTG1) is a newly identified oncogene. We performed a large-scale screening survey to identify related genes expressed in advanced and poorly differentiated serous ovarian carcinoma using cDNA microarray analysis, and found that hPTTG1 is one of highly up-regulated genes in ovarian carcinoma. This study was to examine hPTTG1 mRNA and protein expression in various epithelial ovarian carcinoma,analyze the relationship of its expression level with FIGO stage and histological grade, and explore the functional role of hPTTG1 in ovarian carcinoma pathogenesis. METHODS: HPTTG1 mRNA expression in 27 cases of epithelial human ovarian carcinoma, and 4 cases of normal ovary was assessed with non-competitive reverse transcription polymerase chain reaction (RT-PCR), and hPTTG1 protein expression in these 27 cases of human ovarian carcinoma, and 18 cases of normal ovary was examined by immunohistochemistry. RESULTS: HPTTG1 mRNA expression level in normal ovary was low, while in ovarian carcinoma was significantly higher than that in normal counterparts (P < 0.01). Fold increase of ovarian cancer tissues to normal ovary tissues is 1.1-4.8 (median 2.4).HPTTG1 mRNA high expression level was related to poor tumor differentiation (r = 0.686, P < 0.05), but the correlation with FIGO stage was not detected. HPTTG1 protein was expressed in all cases of ovarian carcinoma, but not in normal ovaries. CONCLUSIONS: Increased hPTTG1 expression may be an important factor involved in early tumorogenesis, and may be associated with poor tumor differentiation. HPTTG1 could be a potential molecular marker of epithelial ovarian carcinoma.

Carcinoma, Endometrioid↗

PubMed2003

Cerebral perfusion SPECT imaging for assessment of the effect of hyperbaric oxygen therapy on patients with postbrain injury neural status.

OBJECTIVE: To evaluate the effects of hyperbaric oxygen (HBO) therapy on patients with postbrain injury neural status. METHODS: Two to 4 courses of HBO therapy and/or medications were used to treat 320 patients who were randomly divided into two groups. Assessment was made with (99m)Tc-ethyl cysteinate dimer ( (99m)Tc-ECD) single photon emission computed tomography (SPECT) before and after treatment. RESULTS: There was a significant difference between the HBO therapy group and the non-HBO therapy group. HBO therapy was superior to medication treatment alone in the recovery of clinical symptoms, control of epilepsy, and resolution of hydrocephalus (P<0.01). CONCLUSIONS: HBO therapy has specific curative effects on patients with postbrain injury neural status, and (99m)Tc-ECD SPECT could play an important role in diagnosing postbrain injury neural status and monitoring the therapeutic effects of HBO.

Adolescent↗

PubMed2002

Comparative 17beta-estradiol response and lipoprotein interactions of an avian apolipoprotein.

Apolipoprotein D (apo D), a member of the lipocalin protein family, has been identified and cloned in several mammalian species; its physiological functions, however, remain poorly understood. As with other lipocalins, apo D can bind small hydrophobic ligands. Lipids and hormones, such as cholesterol, arachidonic acid, and progesterone can bind to apo D; but the physiological significance of these interactions is not clear. We previously reported the existence of an avian (Gallus domesticus) apo D-like protein, and indicated a possible role for it in reproduction. This report provides a further comparative characterization of this avian protein. Evidence is presented that the putative avian apo D, like some (e.g., human) but not other (e.g., rat) mammalian apo Ds, preferentially associates with high density lipoproteins (HDL) in the circulation. These results confirm the apolipoprotein nature of the avian apo D-like protein, and indicate that it has conserved the HDL-interaction property of some mammalian apo Ds. The response of circulatory levels of the avian protein to 17beta-estradiol treatment is also examined. Large estrogen-dependent increases are known to occur in the circulatory levels of some avian apolipoproteins, such as apo B and vitellogenins, that represent major yolk precursors and nutrient sources for the embryo. Although the avian apo D-like protein is also a known yolk precursor, the minor estrogen-dependent increase observed for this apolipoprotein (less than 7% that of apo B) distinguishes it from the major yolk-precursor apolipoproteins. The response of the avian apo D-like protein to 17beta-estradiol is more like that of other yolk precursor proteins that transport regulatory molecules such as vitamin A and thyroid hormones.

Animals↗

PubMed2002

[Establishment and biological characteristics of an immortalized human ovarian sarcomatoid carcinoma cell line BUPH:OVSC-2].

BACKGROUND & OBJECTIVE: Cell immortalization technique has been an important method to establish cell lines with expected phenotype. However, there was few report about the establishment of immortalized human ovarian carcinoma cell lines. The purpose of this study was to establish an immortalized human ovarian sarcomatoid carcinoma cell line, and to investigate its biological characteristics. METHODS: A specimen derived from metastatic tumor of a human ovarian sarcomatoid carcinoma in abdominal wall was obtained and cultured in vitro. The 10th passage was transfected with SV40 T gene, colonies were isolated by G418 selection and expanded to immortalized cell lines. The morphology of the cells was observed by microscope and electromicroscope, Growth curve, karyotype analysis, culturing in soft agar, nude mice transplantation, immunohistochemistry, etc. were used to investigate its biologic characteristics. The biologic characteristics of BUPH: OVSC-2 were compared with its original cells. RESULTS: After transfection and selection, an immortalized ovarian carcinoma cell line BUPH: OVSC-2 was established. The cell line has been maintained for over 90 passages. The H&E stain finding of transplanted tumor showed that the cells were morphologically sarcomatoid. However, the transmission electron microscopic observation exposed its epithelial origin. The cells grew exuberantly and had high malignant characteristics. Comparative studies revealed that the biological properties of BUPH: OVSC-2 and its original cells were identical. CONCLUSIONS: BUPH: OVSC-2 was demonstrated as an immortalized human ovarian sarcomatoid carcinoma cell line with high malignancy. It retains similar properties of their parental cells and could be a useful model for the study of human ovarian sarcomatoid carcinoma.

Cell Division↗