Biomedical subjects

Wen Wang

Publications and source records attributed to Wen Wang.

At least 73 records · Page 4Linked to original sources

PubMed2004

Duplication-degeneration as a mechanism of gene fission and the origin of new genes in Drosophila species.

Gene fission and fusion, the processes by which a single gene is split into two separate genes and two adjacent genes are fused into a single gene, respectively, are among the primary processes that generate new genes. Despite their seeming reversibility, nothing is known about the mechanism of gene fission. Because the nucleotide sequences of fission genes record little about their origination process, conventional analysis of duplicate genes may not be powerful enough to unravel the underlying mechanism. In a survey for young genes in species of the Drosophila melanogaster subgroup using fluorescence in situ hybridization, we identified a young gene family, monkey king, whose genesis sheds light on the evolutionary process of gene fission. Its members originated 1-2 million years ago as retroposed duplicates and evolved into fission genes that separately encode protein domains from a multidomain ancestor. The mechanism underlying this process is gene duplication with subsequent partial degeneration.

Animals↗

PubMed2004

Neural network approach for modification and fitting of digitized data in reverse engineering.

Reverse engineering in the manufacturing field is a process in which the digitized data are obtained from an existing object model or a part of it, and then the CAD model is reconstructed. This paper presents an RBF neural network approach to modify and fit the digitized data. The centers for the RBF are selected by using the orthogonal least squares learning algorithm. A mathematically known surface is used for generating a number of samples for training the networks. The trained networks then generated a number of new points which were compared with the calculating points from the equations. Moreover, a series of practice digitizing curves are used to test the approach. The results showed that this approach is effective in modifying and fitting digitized data and generating data points to reconstruct the surface model.

Algorithms↗

PubMed2004

Morphology of spiroplasmas in the Chinese mitten crab Eriocheir sinensis associated with tremor disease.

The structure of spiroplasmas in the Chinese mitten crab associated with tremor disease was studied by transmission electron microscopy techniques, including both negative staining and ultrasectioning. A spiral structure, which is a typical form of spiroplasmas, could be detected and the observations showed for the first time the presence of spiroplasmas in the cells of the crab. Propagation of spiroplasmas within the cells presented various forms that could be sorted into three morphological types: rounded, regular helical, and pleiomorphic or intermediate forms. The spiroplasmas appeared as round bodies during the fallow stage of development or under poor conditions. They showed various shapes such as helices, saccate, branched, tadpole-like and tortoise-like structures while growing, and became long and congregated in late stages of development. When spiroplasmas were isolated from chicken eggs and cultured in M1D medium they appeared to undergo similar morphological changes to those in the crab. The spiroplasmas contained chromatin filaments and peripheral ribosome-like granules and were delimited by distinct unitary membranes. Average diameters were calculated at 0.1 to 0.35 microm for rounded forms and 0.1-0.2 microm for helical or long forms, and they varied in length from 3-12 microm.

Animals↗

PubMed2004

A spiroplasma associated with tremor disease in the Chinese mitten crab (Eriocheir sinensis).

An epidemic of tremor disease has been a serious problem in Chinese mitten crabs, Eriocheir sinensis, in China in recent years. The disease-causing agent was previously considered to be a rickettsia-like organism. Here, analysis of the 16S rRNA gene sequence, light and electron microscopy and cultivation in vitro were used to identify the agent. Sequence analysis of the 16S rRNA gene found it to have 98 % identity with that of Spiroplasma mirum. The agent was able to be passed through membrane filters with pores 220 nm in diameter and could be cultivated by inoculating the yolk sac of embryonated chicken eggs and M1D medium. Rotary motion and flexional movement were seen by light microscopy, and electron microscopy showed that the organism had a helical morphology and lacked a cell wall. The organism produced small colonies with a diameter of 40-50 microm after 17-25 days of incubation on solid M1D medium. The agent was found in blood cells, muscles, nerves and connective tissues of crabs inoculated with a filtrate of yolk sacs or with cultures grown in M1D medium, and it was similar in structure to those grown in eggs and cultivation broth. Disease was reproduced by experimental infection with the cultivated organisms. This study has demonstrated that the causative agent of tremor disease in the Chinese mitten crab is a member of the genus Spiroplasma. This is believed to be the first time a spiroplasma has been found in a crustacean. These findings are not only significant for studies on pathogenic spiroplasmas, but also have implications for studies of freshwater ecology.

Animals↗

PubMed2004

Nucleotide variation and recombination along the fourth chromosome in Drosophila simulans.

The fourth chromosome of Drosophila melanogaster and its sister species are believed to be nonrecombining and have been a model system for testing predictions of the effects of selection on linked, neutral variation. We recently examined nucleotide variation along the chromosome of D. melanogaster and revealed that a low average level of recombination could be associated with considerably high levels of nucleotide variation. In this report, we further investigate the variation along the fourth chromosome of D. simulans. We sequenced 12 gene regions evenly distributed along the fourth chromosome for a worldwide collection of 11 isofemale lines and 5 gene regions in a local population of 10 isofemale lines from South America. In contrast to predictions for regions of very low recombination, these data reveal that the variation levels in many gene regions, including an intron region of the ci gene, vary considerably along the fourth chromosome. Nucleotide diversity ranged from 0.0010 to 0.0074 in 9 gene regions interspersed with several regions of greatly reduced variation. Tests of recombination indicate that the recombination level is not as low as previously thought, likely an order of magnitude higher than that in D. melanogaster. Finally, estimates of the recombination parameters are shown to support a crossover-plus-conversion model.

Animals↗

PubMed2004

Co-existence of calcium-binding proteins and gamma-aminobutyric acid or glycine in neurons of the rat medullary dorsal horn.

BACKGROUND: We investigated the co-expression of calbindin-D28k (CB), calretinin (CR) and parvalbumin (PV, a combination of the three is referred to as CaBPs) with gamma-aminobutyric acid (GABA) or glycine in neurons of the rat medullary dorsal horn (MDH). METHODS: Immunofluorescence histochemical double-staining for CaBPs and GABA or glycine was performed on the sections from rat MDH. RESULTS: CB-, CR-, PV-, GABA- and glycine-like immunoreactive (LI) neurons were differentially observed in all layers of the MDH, but particularly in lamina II. Neurons that exhibited immunoreactivity for both CaBPs and GABA or glycine were also observed mainly in lamina II. A few of them were found in laminae I and III. The percentages of neurons which co-expressed CB/GABA or CB/glycine out of the total numbers of CB- and GABA-LI neurons or CB- and glycine-LI neurons were 5.3% and 12.1% or 4.1% and 10.0%, respectively. The ratios of CR/GABA or CR/glycine co-existing neurons out of the total numbers of CR- and GABA-LI neurons or CR- and glycine-LI neurons were 5.8% and 7.6% or 4.4% and 7.1%, respectively. The rates of PV/GABA or PV/glycine co-localized neurons out of the total numbers of PV- and GABA-LI neurons or PV- and glycine-LI neurons were 11.1% and 5.1% or 9.9% and 5.1%, respectively. CONCLUSION: The results indicate that some neurons in the MDH contain both CaBPs and GABA or glycine.

Animals↗

PubMed2004

[A study on the relationship between interleukin-4 promoter polymorphism and asthma in a Xinjiang Uyger population].

OBJECTIVE: To investigate the potential association of interleukin-4 (IL-4) polymorphism-589 (C/T) with specific clinical phenotypes of asthma in Xinjiang Uygur population. METHODS: Ninety-three Uyger asthmatics [asthmatic group (A), mild 30 (A(1)), moderate 32 (A(2)), severe 31 (A(3)); nocturnal asthma 41 (A(I)), non-nocturnal asthma 52 (A(II))] in whom linkage of asthma and atopy to chromosome 5q(31 - 33) was suggested and 62 normal healthy controls (B group) with the same ethnicity nearby Xinjiang Hetian region were investigated. The IL-4-589 (C/T) polymorphism was genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. The serum eosinophil cationic protein (ECP) and total IgE and specific aeroallergens were detected using a Pharmacia UniCAP 100 type instrument, and pulmonary ventilatory function was measured by FEV(1)% and PEF. RESULTS: The IL-4 polymorphism-589 (C/T) frequency of the heterozygous CT was 42 (45.1%), homozygous CC 29 (31.2%), and homozygous TT 22 (23.7%) in A group. The frequency of the heterozygous CT was 26 (41.9%), homozygous CC 21 (33.9%), and homozygous TT 15 (24.2%) in B group. There were no significant differences in the distributions of the three genotypes between A group and B group (P > 0.05). The frequency of the homozygous CC was 39.0% in the A(I) group as compared to 25.0% in the A(II) group, the difference being significant (P = 0.026). The frequency of the heterozygous CT was 40% (12/30) in A(1) group, 41% (13/32) in A(2) group and 55% (17/31) in A(3) group. There were significant differences in the distributions of the three genotypes among A(1), A(2) and A(3) group (all P < 0.05). The total serum IgE levels were (75.2 +/- 43.2) kU/L and (52.3 +/- 22.4) kU/L in A group and B group respectively, and there was no significant difference in the levels of total serum IgE among the genotypes in both A and B groups (P > 0.05). The serum ECP levels were (7.9 +/- 5.4) microg/L and (4.8 +/- 1.9) microg/L in A group and B group respectively, the difference being significant between the two groups (P < 0.01). The positive rate of specific IgE antibody was 18.3% (17/93), and 0% (0/62) in A group and B group respectively, and there was significant difference between the two groups (P < 0.01). CONCLUSIONS: It is suggested that the IL-4 promoter-589 (C/T) polymorphism may be associated with nocturnal phenotypes of asthma, but not associated with pulmonary ventilatory function (P > 0.05) and serum total IgE level in this Xinjiang Uyger population.

Adolescent↗

PubMed2004

[Expression of GST-PRL-2 fusion protein in prokaryotic cells and preparation of Hen egg yolk immunoglobulin (IgY) against PRL-2].

AIM: To express phosphatase 2 of regenerating liver (PRL-2) fusion protein in E.coli and to prepare specific hen egg yolk immunoglobulin(IgY) against PRL-2. METHODS: A full-length human PRL-2 gene coding sequence was cloned into expression vectors pGEX-4T-2 and pET21a, then transformed into E.coli. Fusion protein GST-PRL-2 was expressed in E.coli via IPTG induction. The expressed proteins were purified from lysates through Glutathione Sepharose 4B and the Ni-NTA agarose columns, respectively. Egg-laying hens were immunized using the purified GST-PRL-2 with Freund's complete or incomplete adjuvant. The specificity of the resulting antibody was identified by Western blot. RESULTS: A high level of expression of target protein was detected by Western blot after IPTG induction and purified protein was obtained through Glutathione Sepharose 4B and the Ni-NTA affinity chromatography agarose columns, respectively. Western blot analysis showed that the anti-PRL-2 polyclonal antibody can recognize 6 x His-PRL-2 fusion protein. CONCLUSION: The hen egg yolk immunoglobulin(IgY) against PRL-2 expressed in E.coli has good specificity which provides an useful reagent for the detection of PRL-2.

Animals↗

PubMed2004

[Logistic analysis on risk factors related to smear positive pulmonary tuberculosis].

OBJECTIVE: To explore the risk factors on relapsing tuberculosis related to smear positive pulmonary tuberculosis which had been cured for five years. METHODS: Patients with smear positive pulmonary tuberculosis registered in 1995 from ten countries in Hubei province were studied and logistic regression was used for data analysis. RESULTS: The 5-year relapse rate of smear positive pulmonary tuberculosis was 3.85 percent. Risk factors related to relapse would include being non-modeled county, negative smear after treated for three months, the class of retreatment, management of non-DOTS, method of chemotherapy and patients that did not get treated by the tuberculosis institute, with odds ratios of 0.15, 4.62, 3.68, 5.88 and 6.47, respectively. CONCLUSION: Effect standard, regulation DOTS and the centralized management measure might have had effects on decreasing the relapse rate.

Adolescent↗

PubMed2004

The ingestion of Ginkgo biloba extract (EGb 761) inhibits arachidonic acid-mediated platelet aggregation and thromboxane B2 production in healthy volunteers.

Twelve non-diabetic volunteers (age = 39 +/- 13 years, BMI = 23.5 +/- 3.5) undertook a randomized double-blind placebo-controlled crossover study in which they ingested either 120 mg of EGb 761 or a placebo daily for 3 months and then switched to the other test capsules for the next 3 months. Platelet aggregation in platelet-rich plasma (PRP) was performed at the end of each 3-month arm, with or without 1-min incubation with graded doses of EGb 761. In the placebo cycles, AA-stimulated TXB2 production was 2581 +/-1337 pg/10(6) platelets (range 897-5485) compared to 1668 +/- 992 pg/10(6) platelets (range 6-1668) in the EGb 761 cycles (p < 0.005). Incubation of PRP with EGb 761 (150 microg/ml) completely inhibited platelet aggregation accompanied by inhibition of TXB2 synthesis in all subjects both in the placebo (<200 pg TXB2/10(6) platelets) and EGb 761 cycles (< 120 TXB2/10(6) platelets) (p < 0.0001). These results support EGb 761-mediated inhibition of platelet TXB2 synthesis in vivo.

Adult↗

PubMed2003

Prospective study of serum vitamin E levels and esophageal and gastric cancers.

Participants in the General Population Trial, a randomized nutrition intervention trial in Linxian, China, who received a combination of selenium, beta-carotene, and vitamin E supplements, had statistically significantly lower cancer mortality rates than those who did not receive the supplements. In the current study, we used a case-cohort design to examine the association between pre-trial serum vitamin E levels and the risks of developing esophageal and gastric cancers during the trial. We measured serum alpha- and gamma-tocopherol and cholesterol levels in 1072 case patients with incident esophageal squamous cell carcinoma (ESCC), gastric cardia cancer (GCC), or gastric noncardia cancer (GNCC) and in 1053 control subjects. The relative risks for comparisons of the highest to the lowest quartiles of serum alpha-tocopherol were 0.63 (95% confidence interval [CI] = 0.44 to 0.91) for ESCC, 0.84 (95% CI = 0.55 to 1.26) for GCC, and 2.05 (95% CI = 0.89 to 4.75) for GNCC. Serum gamma-tocopherol level was not associated with the incidence of any of these cancers. Our findings provide support for the role of alpha-tocopherol in the etiology of upper gastrointestinal cancers.

Adult↗

PubMed2003

N- and C-terminal modifications of negamycin.

Negamycin 1 is a bactericidal antibiotic with activity against Gram-negative bacteria, and served as a template in an antibiotic discovery program. An orthogonally protected beta-amino acid derivative 3a was synthesized and used in parallel synthesis of negamycin derivatives on solid support. This advanced intermediate was also used for N- and C-terminal modifications using solution-phase methodologies. The N-terminal modifications have resulted in the identification of active analogues, whereas the C-terminal modifications resulted in complete loss of antibacterial activity. The N-methyl negamycin analogue, 19a, inhibits protein synthesis (IC(50)=2.3 microM), has antibacterial activity (Escherichia coli, MIC=16 microgram/mL), and is efficacious in an E. coli murine septicemia model (ED(50)=16.3mg/kg).

Amino Acids, Diamino↗

PubMed2003

Decomposition of benzene in air streams by UV/TiO(2) process.

Photocatalytic decomposition of gaseous benzene at room temperature was studied with a fixed-bed annular reactor using titania as the photocatalyst. The effects of humidity, UV light intensity and benzene concentration on the conversion and mineralization of benzene were presented. Experimental results can be adequately described by using the Langmuir-Hinshelwood (L-H) kinetic model. The concentration distribution of benzene in the annular reactors of various dimensions can be described by combining the reactor design equation with L-H kinetics. Deactivation of catalyst was observed and attributed to the adsorption of reaction intermediates on TiO2 surface. The deactivated TiO2 catalyst could be photochemically regenerated by ozone-purging in the presence of humidity.

Air Pollution↗

PubMed2003

Fatal abdominal aortic compression associated with thoracic vertebral fracture-dislocation after a short fall.

Abdominal aortic injury after blunt trauma is a rare event, as these injuries occur much less frequently than do those of the thoracic aorta. We present an unusual case of fatal abdominal aortic compression with presumed compression associated with a fracture-dislocation of the T11 vertebral body after a short fall, which to our knowledge is the first reported case of this type.

Journal Article↗

PubMed2003

[Expression and function of apoptosis-related genes Bcl-2/Bax and Fas/Fas L in the course of stress ulcer].

OBJECTIVE: To investigate the correlation between the expressions of apoptosis-promoting gene Bax, apotosis-inhibiting gene Bcl-2, and Fas/FasL in gastric mucosa in the course of stress ulcer. METHODS: Fifty-six rats were exposed to water immersion-restraint stress (WRS) and then randomly divided into 7 groups of 8 rats: WRS 2 h, RS 3.5 h, and 2 h, 5 h, 8 h, 12 h, and 24 h after termination of WRS. Another 8 rats were used as controls. The stomachs of rats were taken out at the above mentioned time points to observe histologically. Terminal deoxynucleatidyl transferase mediated dUTP nick and labeling (TUNEL) technique was used to examine the apoptotic cells in the gastric mucosa. The expression of Bcl-2/Bax protein was examined by immunohistochemical assay. In situ hybridization was used to detect the mRNA expression of Bcl-2, Fas, and FasL. RESULTS: (1) Apototic cells were seen sporadically in the gastric mucosa of the control rats. The number of apoptotic cells began to increase since 2 hours after the beginning of WPS and reached its peak 5 hours after the termination of WRS. Since 8 - 12 hours after the termination of WRS the number of apoptosis began to decrease, however, still remained at a level significantly higher than the normal level (P < 0.05). (2) Fas mRNA and FasL mRNA were not expressed in the controls. Fas mRNA was detected 5 - 8 hours after the termination of WRS at the base of mucosa at a low level and disappeared 8 hours after the termination of WRS. FasL mRNA was detected since WRS 3.5h to 8 hours after the termination of WRS. (3) In normal gastric mucosa, Bcl-1 mRNA and protein were expressed in gastric gland zone at a middle level and Bax protein was expressed in the epithelial cells. In WRS rats Bax protein expression began to be detected in the epithelial cells lining the gastric pits since WRS 2 h, then increased, reached the peak 2 - 5 hours after the termination of WRS, and then gradually decreased and remained a little higher than normal level 24 hours later (P < 0.05). Bcl-2 expression began to decrease since the termination of WRS and then increased 8 - 12 hours after the termination of WRS and reached the normal level 24 hours later (P > 0.05). Correlation analysis showed that the expression of Bax protein was correlated with the quantity of apotosis in gastric mucosa. CONCLUSION: The alterations of Bcl and Bax may be responsible for the development of mucosa lesion and recovery. The expression of Fas/FasL has no effect on the gastric mucosa apoptosis related to WRS. Overexpression of Bcl-2 may inhibit the Fas/FasL induced apoptosis.

Animals↗

PubMed2003

Study on experimental infections of Spiroplasma from the Chinese mitten crab in crayfish, mice and embryonated chickens.

Tremor disease (TD) of the Chinese mitten crab Eriocheir sinensi has become a serious disease in the Chinese freshwater culture industry in recent years. The agent, belonging to Spiroplasma, was purified from yolk and allantoic fluids of chicken embryos and was then inoculated into the body of crayfish, the abdominal cavity of ICR mice and the allantoid of chicken embryos, respectively. Thirty-eight days after the inoculation, the mice and crayfish were dissected and their tissues sampled and observed with both the light and electron microscope. No infection was detected in mouse or crawfish tissue. But when the different tissues from the inoculated embryonated chickens were tested, the agent was detected only in the brain of embryonated chickens. This indicated that the agent represented a neurotropic characteristic in embryonated chickens, just as it had in the crab. This infective characteristic may be due to the development and maturation of host immunity.

Animals↗

PubMed2003

The light transmission and distribution in an optical fiber coated with TiO2 particles.

The light delivery and distribution phenomena along the optical fiber coated with the P-25 TiO(2) particles by dipping was investigated. The surface properties (coverage, roughness and thickness) of the TiO(2) layer coated on the optical fiber were characterized by SEM micrographs. For TiO(2) layer prepared from solutions containing less than 20 wt.% of TiO(2) slurry, the thickness of layer was increased linearly with the TiO(2) slurry content in solutions. The UV light intensity transmitted along a TiO(2)-coated optical fiber decreased more rapidly than that transmitted along a non-coated fiber. Based on the experimental results, the light intensity distribution around a coated optical fiber was modeled to determine the optimum configuration for the design of optical fiber reactors under various operational conditions.

Air Pollution↗

PubMed2003

5-hydroxytryptamine1A receptor is involved in the bee venom induced inflammatory pain.

Injection of bee venom into one hindpaw of rat can elicit acute inflammation together with spontaneous pain, heat hyperalgesia and mechanical hyperalgesia/allodynia in the injected paw. 5-hydroxytryptamine (5-HT)1A receptor is the predominant receptor subtype in the spinal dorsal horn mediating the function of 5-HT in nociception. The goal of the present study is to assess the role of 5-HT1A receptor in the pain associated with the bee venom induced inflammation. Here we showed that 1 or 4 h after a subcutaneous bee venom challenge, expression of 5-HT1A receptor mRNA in the ipsilateral lumbar spinal cord increased significantly by 80.94 or 37.86%, respectively. Antisense oligodeoxynucleotide knockdown of spinal 5-HT1A receptor attenuated spontaneous pain and reversed heat hyperalgesia in rats injected with bee venom. Thus, the present data suggest a facilitating role for 5-HT1A receptor in bee venom induced inflammatory pain.

Animals↗