Biomedical subjects

Z Yao

Publications and source records attributed to Z Yao.

At least 55 records · Page 3Linked to original sources

PubMed2001

[Complete genome sequence analysis of the Hantavirus Z10 strain].

OBJECTIVE: Study on the complete genome sequence of Hantavirus Z10 strain which has been applied for inactivated vaccine production in China, to assess its molecular characteristics and the diversity with other hantaviruses. METHODS: The total RNA were prepared from Z10 virus infected cells and the RT-PCR products was cloned into T vector, sequenced and analyzed by using DNASTAR software. RESULTS: The Z10 complete genome, L segment is 6,553, M segment is 3,615, S segment is 1,701 nucleotides in length, with a single open reading frame encoding 2,151, 1,135, 429 amino acids respectively. Sequence homology comparison showed that the 3 segment nucleotide of Z10 strain were close to HTN type virus, but only 83.6-87.4% homology with other HTN viruses at the nucleotide level. The phylogenetic analysis was made on their nucleotide and amino acid sequences. CONCLUSION: The results firstly demonstrates that Z10 strain is a new subtype of the Hantaan(HTN) type.

Amino Acid Sequence↗

PubMed2001

Comparative cellular catabolism and retention of astatine-, bismuth-, and lead-radiolabeled internalizing monoclonal antibody.

UNLABELLED: Monoclonal antibodies (mAbs) labeled with alpha-emitting radionuclides such as (211)At, (212)Bi, (213)Bi, and (212)Pb (which decays by beta-emission to its alpha-emitting daughter, (212)Bi) are being evaluated for their potential applications for cancer therapy. The fate of these radionuclides after cells are targeted with mAbs is important in terms of dosimetry and tumor detection. METHODS: In this study, we attached various radionuclides that result in alpha-emissions to T101, a rapidly internalizing anti-CD5 mAb. We then evaluated the catabolism and cellular retention and compared them with those of (125)I- and (111)In-labeled T101. T101 was labeled with (211)At, (125)I, (205,6)Bi, (111)In, and (203)Pb. CD5 antigen-positive cells, peripheral blood mononuclear cells (PBMNC), and MOLT-4 leukemia cells were used. The labeled T101 was incubated with the cells for 1 h at 4 degrees C for surface labeling. Unbound activity was removed and 1 mL medium added. The cells were then incubated at 37 degrees C for 0, 1, 2, 4, 8, and 24 h. The activity on the cell surface that internalized and the activity on the cell surface remaining in the supernatant were determined. The protein in the supernatant was further precipitated by methanol for determining protein-bound and non-protein-bound radioactivity. Sites of internal cellular localization of radioactivity were determined by Percoll gradient centrifugation. RESULTS: All radiolabeled antibodies bound to the cells were internalized rapidly. After internalization, (205,6)Bi, (203)Pb, and (111)In radiolabels were retained in the cell, with little decrease of cell-associated radioactivity. However, (211)At and (125)I were released from cells rapidly ((211)At < (125)I) and most of the radioactivity in the supernatant was in a non-protein-bound form. Intracellular distribution of radioactivity revealed a transit of the radiolabel from the cell surface to the lysosome. The catabolism patterns of MOLT-4 cells and PBMNC were similar. CONCLUSION: (211)At catabolism and release from cells were somewhat similar to that of (125)I, whereas (205,6)Bi and (203)Pb showed prolonged cell retention similar to that of (111)In. These catabolism differences may be important in the selection of alpha-radionuclides for radioimmunotherapy.

Alpha Particles↗

PubMed2001

Post-PRK muscular asthenopia and eccentric ablation.

OBJECTIVE: To investigate the relationship between muscular asthenopia post photorefractive keratectomy (PRK) and eccentric ablation. METHODS: 16 eyes of 8 myopia cases whose muscular asthenopia was corrected by subjectively accepted triangular prism after PRK with vision more than 0.8 were followed up for 6-14 months. On the basis of data provided by the pre-PRK, post-PRK and their difference corneal topography, we calculated the real corrected corneal diopter (D) with the Holladay formula and measured the ablating eccentricity (h) and its direction. According to the formula delta approximately Dh, the prism effective value (delta) caused by the eccentric ablation was computed and compared with objectively accepted triangular prism. RESULTS: The subjectively accepted prism was similar to values calculated from the formula. Their mean difference is 0.10 +/- 0.25. The direction of the subjectively accepted prism was in the direction of ablation deviation. CONCLUSIONS: Eccentric ablation was the chief cause of post-PRK muscular visual asthenopia. The triangular prism effective value from eccentric ablation may be estimated by the formula delta approximately Dh. We must pay attention to the diagnosis, treatment and prevention of post-PRK muscular asthenopia.

Adult↗

PubMed2001

Confirmation of susceptibility gene loci on chromosome 1 in northern China Han families with type 2 diabetes.

OBJECTIVE: To confirm previous effort to identify type 2 diabetes susceptibility genes in a Northern Chinese population by conducting a new genome scan with both an increased number of type 2 diabetes families and a new set of microsatellite markers within the previously localized regions. METHODS: A genome scan method was applied. After multiplexed PCR, electrophoreses, genescan and genotyping analysis, we obtained size information for all loci, and then a further study was done by both parametric and non-parametric linkage analysis to investigate the P values and Z values of these loci. RESULTS: We surveyed 34 microsatellite markers which distributed within 5 regions along chromosome 1, and a total of 12,000 genotypes were screened. Evidence of linkage with diabetes was identified for 8 of the 34 loci. All P values of the 8 loci were lower than 0.05, and the highest Z value was 2.17. A very interesting finding is that all 5 markers at the p- terminal 1p36.3-1p36.23 region, spanning a long range of 16.9 cM, were identified to have a low P value of less than 0.05, which suggests that this region may contain multiple susceptibility genes. Regions 4 and 5 also confirmed the previous findings, and we narrowed these two regions to a 2.7 cM and 2.5 cM regions, respectively. CONCLUSIONS: We further confirmed the results gained in the previous genome-wide scan using an increased number of NIDDM families and a new set of microsatellite markers lying within the initially localized regions. The fact that all 5 loci at the p- terminal region displayed a low P value of less than 0.05 suggests that more than 1 susceptibility gene may reside in this region.

Chromosomes, Human, Pair 1↗

PubMed2001

[Analysis on the genetics of Hantavirus S85-46 isolated from Sichuan province].

OBJECTIVE: To understand the molecular and epidemic characteristics of Hantavirus S85-46 isolated from Sichuan province. METHODS: RT-PCR products were amplified from S85-46 virus infected cells, cloned into T vector, sequenced and analyzed using DNASTAR software. RESULTS: The homology of M segment of S85-46 strain and HTN type strain varied from 84.1%-99.7%, compared to 70.4%-70.9% with SEO strains. This result indicated that S85-46 strain belonged to hantavirus. The nucleotide sequence analyses indicated that S85-46 strain, LR1 strain and 76-118 strain were highly homologous. The two latter strains were isolated from Shaanxi province of China and South Korea respectively, which were far from Sichuan province of China. The nucleotide sequence analyses of S segment was similar to M segment. CONCLUSION: The epidemic strains isolated from different regions may have been highly homologous.

China↗

PubMed2001

[Surgical treatment and reconstruction for the patients with advanced-stage tonsillar cancer].

OBJECTIVE: To investigate the operative approach and reconstruction for the patients with advanced-stage tonsillar cancer. METHOD: 7 cases with advanced-stage tonsillar cancer were operated from Dec. 1994 to May 1999. Among them, 5 cases were operated through combined neck-mandible-oral cavity approach (CNMOCA) and with immediate reconstruction. Forearm free skin (FFS) flaps were applied in 3 cases. Pectoralis major myocutaneous (PMM) flaps were applied in 2 cases. 2 other cases were operated separately through approach of oral cavity or lateral pharynx. 6 cases were operated with radical neck dissection. RESULT: 5 cases who were operated through CNMOCA or with reconstruction were followed up from 1 year to 5 years and 3 months. They had not recurrence of tumor and complication. All had function recovery of speech. Swallowing or appearance is satisfactory in the 3 cases with FFS flaps. 2 Other cases died as recurrence of tumor in 1 year and 2 years and 10 months post-operation. CONCLUSION: CNMOCA is able to provide a good exposure method to remove the extensive tumors completely for the patients with advanced stage tonsillar cancer. It is necessary to reconstruct immediately for the patients.

Adult↗

PubMed2001

[Inhibitive effect of puerarin on increased NO production by neonatal cardiomyocytes during hypoxia/reoxygenation injury].

OBJECTIVE: To investigate the effect of puerarin (Pue) on nitric oxide (NO) produced by neonatal rat cardiomyocytes during hypoxia/reoxygenation injury. METHOD: NO contents in the culture supernatants sampled from different groups (control, model, and therapeutic groups with 1, 0.1, 0.01 g.L-1 Pue) at different time were assayed with nitrate reductase method. RESULT: NO content of model increased after reperfusion (P < 0.01), while it increased sharply at 6 h after reperfusion and kept thereafter. Only at 6 h after reperfusion did Pue in these three doses inhibit NO production (P < 0.01) and kept to the 24 h after reperfusion. CONCLUSION: Pue exerts inhibitive effect only after NO production is enhanced sharply during hypoxia/reperfusion injury in a dose-dependent trend.

Animals↗

PubMed2000

Bone morphogenetic protein-15. Identification of target cells and biological functions.

In developing ovarian follicles, the regulation of cell proliferation and differentiation is tightly coordinated. Precisely how this coordination is achieved is unknown, but recent observations have suggested that molecules emitted by the oocyte are involved in the process. The newly discovered oocyte-specific growth factor, bone morphogenetic protein-15 (BMP-15), is one such molecule. At present, nothing is known about the target cells and biological functions of BMP-15. To fill this gap in our knowledge, recombinant BMP-15 and its antibody were produced and used to determine BMP-15 expression and bioactivity. BMP-15 mRNA and protein were shown to be co-expressed in oocytes throughout folliculogenesis, supporting the idea that BMP-15 is a physiological regulator of follicle cell proliferation and/or differentiation. To test this, we used primary cultures of rat granulosa cells (GCs). We found that BMP-15 is a potent stimulator of GC proliferation, and importantly, the mitogenic effect was follicle-stimulating hormone (FSH)-independent. By contrast, BMP-15 alone had no effect on steroidogenesis. However, it produced a marked decrease in FSH-induced progesterone production, but had no effect on FSH-stimulated estradiol production. This result indicates that BMP-15 is a selective modulator of FSH action. In summary, this study identifies GCs as the first target cells for BMP-15. Moreover, it identifies the stimulation of GC proliferation and the differential regulation of two crucial steroid hormones as the first biological functions of BMP-15. Significantly, BMP-15 is the first growth factor that can coordinate GC proliferation and differentiation in a way that reflects normal physiology.

Animals↗

PubMed2000

The assembly of very low density lipoproteins in rat hepatoma McA-RH7777 cells is inhibited by phospholipase A2 antagonists.

In McA-RH7777 cells, the oleate-stimulated assembly and secretion of very low density lipoproteins (VLDL) was associated with enhanced deacylation of phospholipids, which was markedly decreased by inactivation of the cellular phospholipase A(2). Treatment of the cells with antagonists or antisense oligonucleotide of the Ca(2+)-independent phospholipase A(2) (iPLA(2)) significantly inhibited secretion of apoB100-VLDL and triglyceride. Similar inhibitory effect of the iPLA(2) antagonists was observed on apoB48-VLDL secretion, but secretion of high density lipoprotein particles (such as apoAI- and apoB48-high density lipoprotein) or proteins in general was unaffected. The iPLA(2) antagonist did not affect the synthesis of apoB100 or triglyceride, nor did it affect the activities of phospholipase D, phosphatidate phosphohydrolase, or microsomal triglyceride transfer protein. Inactivation of iPLA(2) resulted in impaired apoB100-VLDL assembly as shown by decreased apoB100-VLDL and triglyceride within the microsomal lumen, with concomitant increase in apoB100 association with the microsomal membranes. The inhibitory effect of iPLA(2) antagonists on apoB100-VLDL assembly/secretion could be abated by pretreatment of cells with oleate. Analysis of molecular species of microsomal phosphatidylcholine and phosphatidylethanolamine by electron spray tandem mass spectrometry revealed that the enrichment of oleoyl moieties was altered by the treatment of iPLA(2) antagonist. These results suggest that the oleate-induced VLDL assembly/secretion may depend upon the establishment of membrane glycerolipids enriched in oleoyl chain, a process mediated by the iPLA(2) activity.

Animals↗

PubMed2000

Leaf morphology and cuticular features of Sphenophyllum in the Gigantopteris flora from South China.

Permian specimens of Sphenophyllum with preserved cuticular anatomy have been discovered in Cathaysia and have prompted a detailed re-evaluation of the genus in the Gigantopteris flora in South China. New specimens are described and previously published material is re-examined to clarify taxonomic diversity and to establish geographic and stratigraphic ranges for each species. Recognized taxa include Sphenophyllum apiciserratum sp. nov., S. koboense Kobatake, S. meridionale sp. nov., S. minor (Sterzel) Gu and Zhi, S. sinocoreanum Yabe, S. cf. sinocoreanum Yabe, and S. aff. speciosum (Royle) McClelland. Cuticles of Sphenophyllum apiciserratum and S. koboense are hypostomatic with randomly disposed ordinary cells in intercostal regions. Specific concepts are clarified and unresolved taxonomic problems are discussed. The South China taxa are compared with those from Euramerican, Gondwanan and Angaran floras, and the South China Cathaysian species are found to be taxonomically distinct.

Journal Article↗

PubMed2000

ERK1b, a 46-kDa ERK isoform that is differentially regulated by MEK.

We identified a 46-kDa ERK, whose kinetics of activation was similar to that of ERK1 and ERK2 in most cell lines and conditions, but showed higher fold activation in response to osmotic shock and epidermal growth factor treatments of Ras-transformed cells. We purified and cloned this novel ERK (ERK1b), which is an alternatively spliced form of ERK1 with a 26-amino acid insertion between residues 340 and 341 of ERK1. When expressed in COS7 cells, ERK1b exhibited kinetics of activation and kinase activity similar to those of ERK1. Unlike the uniform pattern of expression of ERK1 and ERK2, ERK1b was detected only in some of the tissues examined and seems to be abundant in the rat and human heart. Interestingly, in Ras-transformed Rat1 cells, there was a 7-fold higher expression of ERK1b, which was also more responsive than ERK1 and ERK2 to various extracellular treatments. Unlike ERK1 and ERK2, ERK1b failed to interact with MEK1 as judged from its nuclear localization in resting cells overexpressing ERK1b together with MEK1 or by lack of coimmunoprecipitation of the two proteins. Thus, ERK1b is a novel 46-kDa ERK isoform, which seems to be the major ERK isoform that responds to exogenous stimulation in Ras-transformed cells probably due to its differential regulation by MEK.

Alternative Splicing↗

PubMed2000

Phosphorylation and destabilization of human period I clock protein by human casein kinase I epsilon.

Period (PER), a central component of the circadian clock in Drosophila, undergoes daily oscillation in abundance and phosphorylation state. Here we report that human casein kinase I epsilon (hCKI epsilon) can phosphorylate human PER I (hPER I). Purified recombinant hCKI epsilon (but not a kinase negative mutant of hCKI epsilon, hCKI epsilon-K38R) phosphorylated hPER I in vitro. When co-transfected with wild-type hCKI epsilon, in 293T cells, hPER I showed a significant increase in phosphorylation as evidenced by a shift in molecular mass. Furthermore, phosphorylation of hPER I by hCKI epsilon caused a decrease in protein stability in hPER I. Whereas phosphorylated hPER I had a half-life of approximately 12 h, unphosphorylated hPER I remained stable in the cell for > 24 h. hPER I protein could also be co-immunoprecipitated with transfected hCKI epsilon as well as endogenous hCKI epsilon, indicating physical association between hPER I and hCKI epsilon proteins in vivo.

Animals↗

PubMed2000

High-field electrical transport in single-wall carbon nanotubes

Using low-resistance electrical contacts, we have measured the intrinsic high-field transport properties of metallic single-wall carbon nanotubes. Individual nanotubes appear to be able to carry currents with a density exceeding 10(9) A/cm(2). As the bias voltage is increased, the conductance drops dramatically due to scattering of electrons. We show that the current-voltage characteristics can be explained by considering optical or zone-boundary phonon emission as the dominant scattering mechanism at high field.

Journal Article↗

PubMed2000

Detection of partially phosphorylated forms of ERK by monoclonal antibodies reveals spatial regulation of ERK activity by phosphatases.

When cells are stimulated by mitogens, extracellular signal-regulated kinase (ERK) is activated by phosphorylation of its regulatory threonine (Thr) and tyrosine (Tyr) residues. The inactivation of ERK may occur by phosphatase-mediated removal of the phosphates from these Tyr, Thr or both residues together. In this study, antibodies that selectively recognize all combinations of phosphorylation of the regulatory Thr and Tyr residues of ERK were developed, and used to study the inactivation of ERK upon mitogenic stimulation. We found that inactivation of ERK in the early stages of mitogenic stimulation involves separate Thr and Tyr phosphatases which operate differently in the nucleus and in the cytoplasm. Thus, ERK is differentially regulated in various subcellular compartments to secure proper length and strength of activation, which eventually determine the physiological outcome of many external signals.

Animals↗

PubMed2000

Microbial production of spider silk proteins.

The remarkable properties of spider dragline silk and related protein polymers will find many applications if the materials can be produced economically. We have demonstrated the production of high molecular weight spider dragline silk analog proteins encoded by synthetic genes in several microbial systems, including Escherichia coli and Pichia pastoris. In E. coli, proteins of up to 1000 amino acids in length could be produced efficiently, but the yield and homogeneity of higher molecular weight silk proteins were found to be limited by truncated synthesis, probably as a result of ribosome termination errors. No such phenomenon was observed in the yeast P. pastoris, where higher molecular weight silk proteins could be produced without heterogeneity due to truncated synthesis. Spider dragline silk analog proteins could be secreted by P. pastoris when fused to both the signal sequence and N-terminal pro-sequence of the Saccharomyces cerevisiae alpha-mating factor gene.

Amino Acid Sequence↗

PubMed2000

A comparison of 99Tcm-MIBI myocardial SPET and electron beam computed tomography in the assessment of coronary artery disease in two different age groups.

The aim of this study was to compare the clinical value of 99Tcm-MIBI single photon emission tomography (SPET) and electron beam computed tomography (EBCT) in the assessment of coronary artery disease (CAD) in different age groups. 99Tcm-MIBI SPET (stress-rest), EBCT and coronary angiography studies were performed in 64 consecutive patients with suspected CAD. The patients were classified into two groups: Group A = 40 patients > 45 years of age and Group B = 24 patients < or = 45 years of age. There were 31 and 14 patients with coronary stenosis > or = 50% as determined by coronary angiography in Groups A and B, respectively. All patients (30 cases) with abnormal 99Tcm-MIBI myocardial SPET and coronary calcification detected by EBCT had significant coronary artery disease, and 93.3% of the patients with normal 99Tcm-MIBI SPET and normal EBCT had normal coronary angiography or < 50% lumen narrowing of the coronary arteries. In Group B, the sensitivity of SPET for detecting CAD was significantly higher than that of EBCT (92.9 vs 42.9%, P < 0.01); the specificity of SPET was comparable to that of EBCT. In Group A, there was no significant difference between SPET and EBCT in terms of sensitivity (93.6 vs 90.3%) or specificity (88.9 vs 55.6%). However, in the detection of individual coronary artery disease, the specificity of SPET was significantly higher than that of EBCT in Group A (94.1 vs 66.7%, P < 0.001). The sensitivity of SPET was again significantly higher than that of EBCT (85.7 vs 38.1%, P < 0.005) in Group B. The accuracy of SPET was higher than that of EBCT in both groups (82.5 vs 67.5%, P < 0.01 in Group A; 93.1 vs 76.4%, P < 0.01 in Group B, respectively). We conclude that 99Tcm-MIBI myocardial perfusion SPET has a higher sensitivity than EBCT in the detection of CAD in patients < or = 45 years old and a higher specificity in patients > 45 years of age. A combination of SPET and EBCT may assess CAD more accurately.

Adult↗

PubMed2000

Flumazenil preconditions cardiomyocytes via oxygen radicals and K(ATP) channels.

We determined whether flumazenil mimics ischemic preconditioning in chick cardiomyocytes and examined the role of intracellular reactive oxygen species (ROS) and ATP-dependent potassium (K(ATP)) channels in mediating the effect. Chick ventricular myocytes were perfused with a balanced salt solution in a flow-through chamber. Cell viability was quantified using propidium iodide, and ROS generation was assessed using the reduced form of 2',7'-dichlorofluorescin (DCFH). Cells were exposed to 1 h of simulated ischemia and 3 h of reoxygenation. Preconditioning was initiated with 10 min of ischemia followed by 10 min of reoxygenation. Alternatively, flumazenil was added to the perfusate for 10 min and removed 10 min before the start of ischemia. Flumazenil (1 and 10 microM) and preconditioning reduced cell death [54 +/- 5%, n = 3; 26 +/- 4%, n = 6 (P < 0.05); and 20 +/- 2%, n = 6 (P < 0.05), respectively, vs. 57 +/- 7%, n = 10, in controls] and increased DCFH oxidation (an index of ROS production) [0.35 +/- 0.11, n = 3; 2.64 +/- 0.69, n = 8 (P < 0.05); and 2.46 +/- 0.52, n = 6 (P < 0.05), respectively, vs. 0.26 +/- 0.05, n = 9, in controls]. Protection and increased ROS signals with flumazenil (10 microM) were abolished with the thiol reductant N-(2-mercaptopropionyl)-glycine (2-MPG, 800 microM), an antioxidant (cell death: 2-MPG + flumazenil, 55 +/- 12%, n = 6; ROS signals: 2-MPG + flumazenil, 0.11 +/- 0.19, n = 6). Treatment with 5-hydroxydecanoate (1 mM), a selective mitochondrial K(ATP) channel antagonist, abolished its protection. These results demonstrate that flumazenil mimics preconditioning to reduce cell death in myocytes. ROS signals with the resultant mitochondrial K(ATP) channel activation are important components of the intracellular signaling pathway of flumazenil.

Adenosine Triphosphate↗

PubMed2000

Chronic alcohol ingestion induces osteoclastogenesis and bone loss through IL-6 in mice.

To investigate the role of IL-6 in alcohol-mediated osteoporosis, we measured a variety of bone remodeling parameters in wild-type (il6(+/+)) or IL-6 gene knockout (il6(-/-)) mice that were fed either control or ethanol liquid diets for 4 months. In the il6(+/+) mice, ethanol ingestion decreased bone mineral density, as determined by dual-energy densitometry; decreased cancellous bone volume and trabecular width and increased trabecular spacing and osteoclast surface, as determined by histomorphometry of the femur; increased urinary deoxypyridinolines, as determined by ELISA; and increased CFU-GM formation and osteoclastogenesis as determined ex vivo in bone marrow cell cultures. In contrast, ethanol ingestion did not alter any of these parameters in the il6(-/-) mice. Ethanol increased receptor activator of NF-kappaB ligand (RANKL) mRNA expression in the bone marrow of il6(+/+) but not il6(-/-) mice. Additionally, ethanol decreased several osteoblastic parameters including osteoblast perimeter and osteoblast culture calcium retention in both il6(+/+) and il6(-/-) mice. These findings demonstrate that ethanol induces bone loss through IL-6. Furthermore, they suggest that IL-6 achieves this effect by inducing RANKL and promoting CFU-GM formation and osteoclastogenesis.

Absorptiometry, Photon↗