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Biomedical subjects

W Wei

Publications and source records attributed to W Wei.

At least 73 records · Page 4Linked to original sources
PubMed2000

Molecular cloning and characterization of a novel human gene containing ankyrin repeat and double BTB/POZ domain.

A novel human gene containing an ankyrin repeat and BTB/POZ domains (BPOZ) was isolated from a human leukocyte cDNA library. The cDNA sequence contains an open reading frame of 1434 bp that encodes 478 amino acid residues with a predicted molecular mass of 53.9 kDa. Sequence pattern analysis shows that BPOZ contains an N-terminal ankyrin repeat, a bipartite nuclear localization signal and two BTB/POZ domains. Using semiquantitative RT-PCR, the BPOZ transcript was found to be ubiquitously expressed in all fetal tissues examined (heart, brain, liver, and kidney) suggesting that BPOZ is involved in basic cellular function. Low expression of BPOZ in adult tissues (normal and hypertrophic heart) suggests that BPOZ mRNA is developmentally regulated and may play a role in developmental processes. Chromosomal localization by radiation hybrid mapping revealed that this gene is localized between D3S1269 and D3S3606 markers corresponding to the region of chromosome 3q21, a region frequently associated with leukemia. It is thus suggested that BPOZ may be functionally involved in protein-protein interaction, perhaps in forming protein complexes, and may have an important role in normal development and in the development of leukemia.

Amino Acid Sequence↗
PubMed2000

On-column derivatization for the analysis of homocysteine and other thiols by capillary electrophoresis with laser-induced fluorescence detection.

On-column derivatization and capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection has been developed for the fully automated assay of homocysteine and other thiols. The unique feature of this CE technique comes from the direct injection of a sample including homocysteine, enabling the derivatization with 4-aminosulfonyl-7-fluoro-2,1,3-benzoxadizole (ABD-F) to be accomplished in the capillary. After the derivatization for 10 min at 50 degrees C, the homocysteine was analyzed within 7 min under an applied electric field of 333 V cm(-1). The detection limit obtained for homocysteine with on-column LIF detection was 5.0 nM, as compared to 2.5 nM with pre-column LIF detection. The method is a very simple, fast, and practical approach for the fully automated assay of homocysteine and other thiols contained in low-volume and low-concentration samples.

Electrophoresis, Capillary↗
PubMed2000

Highly regulated expression of subtilisin-like proprotein convertase PACE4 (SPC4) during dentinogenesis.

Expressions of mRNAs for four subtilisin-like proprotein convertases (SPCs: furin, PACE4, PC6, and PC8) and bone morphogenetic protein 4 (BMP4) in the rat molar tooth during development were analyzed by Northern blotting, reverse transcriptase-polymerase chain reaction (RT-PCR), and in situ hybridization to explore the possible involvement of SPCs in the processing of proBMPs. We found a temporospacial expression of PACE4, but not one of the other SPCs, in this tissue; i.e., RT-PCR analysis revealed that the level of PACE4 mRNA, but not that of the other SPC mRNAs became high around the second postnatal day. This increase was in good accordance with the increase in BMP4 mRNA, indicating an apparent association of these molecules with the differentiation and establishment of functional ameloblasts and odontoblasts. During dentinogenesis, PACE4 mRNA was localized in the ameloblasts and odontoblasts. These observations suggest that PACE4 plays a crucial role in dentinogenesis, especially via the activation of BMPs.

Animals↗
PubMed2000

A valence bond study of the Bergman cyclization: geometric features, resonance energy, and nucleus-independent chemical shift (NICS) values

The Bergman cyclization of (Z)-hex-3-ene-1,5-diynes (1, enediynes), which produces pharmacologically important DNA-cleaving biradicals (1,4-benzyne, 2), was studied by using Hartree-Fock (HF) and density-functional theory (DFT) based valence bond (VB) methods (VB-HF and VB-DFT, respectively). We found that only three VB configurations are needed to arrive at results not too far from complete active space [CASSCF(6 x 6)] computations, while the quality of VB-DTF utilizing the same three configurations improves upon CASSCF(6 x 6) analogous to CASPT2. The dominant VB configuration in 1 contributes little to 2, while the most important biradical configuration in 2 plays a negligible role in 1. The avoided crossing of the energy curves of these two configurations along the reaction coordinate leads to the transition state (TS). As a consequence of the shape and position of the crossing section, the changes in geometry and in the electronic wavefunction along the reaction coordinate are non-synchronous; the TS is geometrically approximately 80% product-like and electronically approximately 70% reactant-like. While the pi resonance in the TS is very small, it is large (64.4 kcal mol(-1)) for 2 (cf. benzene=61.5 kcal mol(-1)). As a consequence, substituents operating on the sigma electrons should be much more effective in changing the Bergman reaction cyclization barrier. Furthermore, additional sigma resonance in 2 results in unusually high values for the nucleus-independent chemical shift (NICS, a direct measure for aromaticity). Similarly, the high NICS value of the TS is due mostly to sigma resonance to which the NICS procedure is relatively sensitive.

Journal Article↗
PubMed2000

beta-amyloid peptide-induced death of PC 12 cells and cerebellar granule cell neurons is inhibited by long-term lithium treatment.

Treatment of rat pheochromocytoma cells (PC 12) cells with beta-amyloid peptide-(1-42) for 24 h induced a concentration-dependent decrease in cellular redox activity in the dose range of 1 to 20 microM. These effects were markedly attenuated by pretreatment with 2 mM LiCl for 7 days, whereas 1-day pretreatment was ineffective. Measurements of live and dead cells by double-staining with fluorescein diacetate and propidium iodide, respectively revealed that protracted lithium pretreatment attenuated PC 12 cell death induced by beta-amyloid-(1-42) and cerebellar granule cell death induced by beta-amyloid-(25-35). Preceding PC 12 cell death, beta-amyloid peptide elicited a slight decrease in protein levels of Bcl-2. Conversely, 7-day pretreatment with lithium resulted in an approximate doubling of Bcl-2 protein levels in cells treated with or without beta-amyloid peptide-(1-42). Lithium-induced Bcl-2 upregulation was temporally associated with the cytoprotective effects of this drug. Thus, lithium protection against beta-amyloid peptide neurotoxicity might involve Bcl-2 overexpression, and lithium treatment for Alzheimer's disease should be reexamined.

Amyloid beta-Peptides↗
PubMed2000

Mid-Pleistocene Acheulean-like stone technology of the Bose basin, South China.

Stone artifacts from the Bose basin, South China, are associated with tektites dated to 803,000 +/- 3000 years ago and represent the oldest known large cutting tools (LCTs) in East Asia. Bose toolmaking is compatible with Mode 2 (Acheulean) technologies in Africa in its targeted manufacture and biased spatial distribution of LCTs, large-scale flaking, and high flake scar counts. Acheulean-like tools in the mid-Pleistocene of South China imply that Mode 2 technical advances were manifested in East Asia contemporaneously with handaxe technology in Africa and western Eurasia. Bose lithic technology is associated with a tektite airfall and forest burning.

Africa↗
PubMed2000

The gene coding for the Hrp pilus structural protein is required for type III secretion of Hrp and Avr proteins in Pseudomonas syringae pv. tomato.

Bacterial surface appendages called pili often are associated with DNA and/or protein transfer between cells. The exact function of pili in the transfer process is not understood and is a matter of considerable debate. The Hrp pilus is assembled by the Hrp type III protein secretion system of Pseudomonas syringae pv. tomato (Pst) strain DC3000. In this study, we show that the hrpA gene, which encodes the major subunit of the Hrp pilus, is required for secretion of putative virulence proteins, such as HrpW and AvrPto. In addition, the hrpA gene is required for full expression of genes that encode regulatory, secretion, and effector proteins of the type III secretion system. hrpA-mediated gene regulation apparently is through effect on the mRNA level of two previously characterized regulatory genes, hrpR and hrpS. Ectopic expression of the hrpRS gene operon restored gene expression, but not protein secretion, in the hrpA mutant. Three single amino acid mutations at the HrpA carboxyl terminus were identified that affect the secretion or regulatory function of the HrpA protein. These results define an essential role of the Hrp pilus structural gene in protein secretion and coordinate regulation of the type III secretion system in Pst DC3000.

Amino Acids↗
PubMed2000

Relationship between extracellular matrix both in choroid plexus and the wall of lateral ventricles and intraventricular hemorrhage in preterm neonates.

Pathogenesis of intraventricular hemorrhage (IVH) may relate to immature vessels. However extracellular matrix--such as Type IV collagen, laminin, and fibronectin has a direct bearing on the development of the endothelium and the immature microvessel. Twenty specimens taken from lateral ventricular walls and choroid plexus in 10 preterm neonates who died of intraventricular hemorrhage and another 10 preterm neonates who died of non-intraventricular hemorrhage, were marked with antibodies against Type IV collagen, laminin, and fibronectin. Average areas of positive staining around the microvessels in the IVH group showed less staining than that in the non-IVH group (P < 0.05), and the microvessel count of discontinuous positive staining in IVH group was more than that in non-IVH group, P < 0.05. We conclude that lacking Type IV collagen, laminin, and fibronectin may result not only in an incomplete basement membrane in choroid plexus and subependymal immature microvessels but also may be a factor contributing to IVH in preterm neonates.

Cerebral Hemorrhage↗
PubMed2000

Platelet fibrinogen in the patients with idiopathic bleeding platelet disorder.

The changes of platelet fibrinogen in patients with obscure cutaneous mucosal bleeding and their relation with disease were evaluated. By using flow cytometry and Western blot, the platelet binding site of fibrinogen and the expression of platelet fibrinogen in 8 cases of obscure bleeding were detected. The results showed that platelet surface binding sites of fibrinogen were 65.38 +/- 3.62 in the resting state and 65.25 +/- 5.78 after activated by adenosine diphosphate, showing no significant difference as compared with control group (P > 0.05). The expression of platelet fibrinogen was obviously decreased in 4 patients and increased in one case as compared with control group. It was concluded that the binding sites of fibrinogen on the platelet surface were normal in the patients with idiopathic bleeding platelet disorder. The abnormal of platelet fibrinogen might be one of hemorrhagic reasons in partial patients.

Adult↗
PubMed2000

The relationship between activated protein C-resistance and recurrent abortion.

The activated protein C-resistance (APC-R) method based on APTT was used in 40 non-pregnant multiparas (control group) and 55 patients with abortion of unknown origin (experimental group) in order to explore the relationship between APC-R and recurrent abortion. A significant difference in APC-R-positive rate was found (P < 0.01) between control group and experimental group, with the rate being 5% in the controls and 25.5% in the experimental group. And the APC-R-positive rates in the patients with only twice abortions and the patients over-3-time abortions were 22.6% and 29.2%, respectively (P > 0.05). The APC-R-positive rate, which was 37.9% in the patients of late abortion, was much higher than that in the patients of early abortion. It is concluded that APC-R has something to do with recurrent abortion, and is closely related to late abortion, but bears no obvious relationship with times of abortions.

Abortion, Habitual↗
PubMed2000

Double cell bulk acoustic wave sensor for ion chromatographic study of the relation between magnesium and growth of organisms.

An ion chromatography (IC) method with a double cell bulk acoustic wave (DCBAW) detector was used for the detection of magnesium concentration decrease during the culture of whole cells. The detector parameters were optimized according to its theoretical equation, including the cell constants and the background conductance of the adjusting cell. A low temperature coefficient and thus high sensitivity were obtained by this method. The detection limit is 0.01 ppm, and the linear range is 0.05-50 ppm. A new mathematical model was developed to describe the growth of the cell. The baseline for this model is the concept that a noninteractive growth process occurs among perfectly substitutable nutrients if the locus of points of the substrate concentrations producing equal growth rate is linear. The monitoring results agreed well with the calculated results.

Acoustics↗
PubMed2000

Cyclin D1 expression in oral squamous cell carcinomas: clinicopathological relevance and correlation with p53 expression.

The aim of the present study is to study the relationship between cyclin D1 and the clinicopathological features of oral squamous cell carcinomas. The cyclin D1 and p53 expression in oral squamous cell carcinomas from 56 patients (45 men, 11 women) was studied by immunohistochemistry using monoclonal antibodies. The correlation between cyclin D1 and the clinicopathological features of the oral cancers was evaluated. Cyclin D1 expression was found in 63% of oral squamous cell carcinomas; it was often weak but was more frequently positive in high-grade lesions (P=0.019). The expression was positively correlated with p53 expression (P= 0.06). Radiation therapy did not alter the expression of either cyclin D1 or p53 proteins. Expression of these proteins was not related to the age, gender or survival of the patients, or to stages of the tumors. The cyclin D1 expression was more frequently seen in patients with squamous cell carcinomas of oropharynx, palate, floor of mouth and gingiva. To conclude, cyclin D1 was frequently expressed in oral squamous cell carcinomas. This expression was related to the grade of the tumors and was not similar in various regions in the oral cavity, which may indicate the different tumor biology of cancers from these regions.

Adult↗
PubMed2000

Indirect determination of thiocyanate with ammonium sulfate and ethanol by extraction-flotation of copper.

A new method for the indirect determination of thiocyanate with ammonium sulfate and ethanol by extraction-flotation of copper in the presence of ascorbic acid is described. A small amount of Cu(II) is reduced to Cu(I) by ascorbic acid, then Cu(I) is precipitated with SCN-. In the course of phase separation of ethanol from water, the precipitated CuSCN stays in the interface of ethanol and water. A good linear relationship is observed between the flotation yield of Cu(II) and the amount of SCN-. Using 1.0 ml of 1 x 10(-3) M ascorbic acid solution, 50 micrograms of Cu(II), 3.5 g of (NH4)2SO4 and 3.0 ml of ethanol with a total volume of 10 ml, the concentration of thiocyanate could then be determined by determining the flotation yield of Cu(II). The detection limit for thiocyanate is 5 x 10(-5) M. Every parameter was optimized and the reaction mechanism was studied. The method is simple and rapid and it was successfully applied to the determination of thiocyanate in urine and saliva of smokers and non-smokers and in venous blood of patients infused with sodium nitroprusside.

Ammonium Sulfate↗
PubMed2000

Expression of kininogens in the connective tissue-type mast cells of the rat.

The connective tissue-type mast cells present in the submandibular gland (SMG) and peritoneal cavity of rats were found to express kininogens (KGs), the expression of which was demonstrated by Western blotting, reverse transcription-polymerase chain reaction (RT-PCR), RT-PCR Southern blotting, and light- and electron-microscopic immunocytochemistry. In the SMG, the analysis of cDNA amplified by RT-PCR revealed that the molecular species of mRNAs expressed were high-molecular-weight (HMW)-K KG and T-I KG. Light microscopic immunocytochemistry exclusively localized the KG protein(s) in the mast cells present in the SMG. The signals in the mast cells were very strong, but no positive reaction was observed in the granular convoluted tubular cells, acinar cells or striated duct cells. As determined by using electron microscopy, extremely strong labelling with immunogold was observed in the secretory granules of the mast cells, but no labelling in their nucleus or cytoplasm. Analysis by Western blotting and RT-PCR Southern blotting indicated that both protein and mRNA of KGs were present in the mast cells separated from the peritoneal cavity, indicating de novo synthesis of KG in these cells. Preliminary experiments implied that the connective tissue-type mast cells in other rat tissues also expressed KG.

Animals↗
PubMed2000

The impact of educational videotapes on water contact behaviour of primary school students in the Dongting Lakes region, China.

Multimedia has become increasingly important in educational programmes in schools in all societies, and has potential value for health education. We developed a video and a comic book on the transmission and prevention of schistosomiasis for use in primary schools in endemic areas of China. The material was designed to increase children's knowledge of schistosomiasis as an environmental disease and to encourage them to reduce their contact with unsafe water sources. To test the effectiveness of the video and booklet, a quasi-experimental study was conducted among 1,739 children in 50 primary schools in the Dongting Lake region. A self-administered questionnaire pre- and post-intervention showed a significant increase in knowledge about schistosomiasis in the intervention schools. Significantly, this change was associated with a decrease in contact with unsafe water sources, as established from water contact observations. This behavioural change suggests the value of short, targeted educational interventions to decrease risk of infection.

Adolescent↗