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Biomedical subjects

C Wei

Publications and source records attributed to C Wei.

At least 37 records · Page 2Linked to original sources
PubMed2001

The cardiovascular actions of omapatrilat in spontaneously hypertensive rats.

Omapatrilat is a newly developed vasopeptidase inhibitor that inhibits both angiotensin-converting enzyme (ACE) and neutral endopeptidase and has potent antihypertensive efficacy. However, the specific effect of omapatrilat on cardiac function and left ventricular hypertrophy with hypertension remains controversial. Therefore, we investigated the effect of omapatrilat on blood pressure, cardiac hypertrophy, and cardiac function in spontaneously hypertensive rats (SHR). Studies were performed in SHR that received vehicle (n = 9), omapatrilat (n = 10), or fosinopril (ACE inhibitor, n = 7) by daily gavage for 56 days. Systolic blood pressure (SBP) and mean blood pressure (MBP) were measured by tail plethysmography. Left ventricular fractional shortening and left ventricular mass were measured by echocardiography at day 56. Omapatrilat and fosinopril significantly decreased SBP and MBP from day 1 through day 56, and omapatrilat markedly reduced SBP and MBP compared with fosinopril from day 21 to day 56. Although both omapatrilat and fosinopril decreased left ventricular mass and left ventricular mass-to-body weight ratio with increased LV fractional shortening, omapatrilat had a more potent effect on the reduction of left ventricular mass and improvement of cardiac function. This study shows that in SHR, omapatrilat mediated a potent and stable antihypertensive effect and a reduction in left ventricular mass with improvement of cardiac function, compared with ACE inhibition alone.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2001

Chemical, microbiological, and AromaScan evaluation of mahi-mahi fillets under various storage conditions.

The quality for mahi-mahi stored at 1.7, 7.2, and 12.8 degrees C for 0, 1, 3, and 5 days was determined using biogenic amine analysis, microbial counts, and sensory evaluation (by a sensory test panel and an AromaScan). Biogenic amines in methanol extracts from mahi-mahi samples were analyzed using capillary electrophoresis (CE) with ultraviolet detection at 210 nm and a gas chromatography (GC) method that can simultaneously determine the contents of putrescine, cadaverine, histamine, spermidine, and spermine within 20 min after pentafluoropropionic anhydride derivatization. A good correlation R2= 0.99) was found between CE and GC methods for detecting histamine in mahi-mahi. Fish quality deteriorated and correlated with increasing microbial numbers. Biogenic amines may be useful indicators for mahi-mahi quality and safety. AromaScan was able to correlate quality changes for mahi-mahi in microbiological and sensory analyses.

Animals↗
PubMed2001

Tumours can act as adjuvants for humoral immunity.

Tumour cells transfected with cDNAs encoding non-self proteins were used to investigate the ability of the immune system to respond to immunogenic antigens expressed by tumours. Secreted, intracellular and surface proteins were used as model antigens, as these reflect the potential forms of tumour antigens. Syngeneic BALB/c mice injected with viable line 1 lung carcinoma or EMT6 mammary tumour cells secreting ovalbumin (OVA) or prostate-specific antigen (PSA) produced very high immunoglobulin G (IgG) antibody titres, equivalent to those of mice injected with protein in Freund's complete adjuvant (FCA). Secretion of the antigens was not necessary as tumour cells expressing a cell-surface antigen (HER-2/Neu) or an intracellular antigen - green fluorescence protein (GFP) - also generated high-titre antigen-specific IgG antibodies. In interleukin-4 (IL-4)-deficient mice, both IgG1 and IgG2a were produced in response to OVA administered in FCA, whereas in response to tumour-produced antigen, the antibodies switched from predominantly IgG1 to IgG2a, indicating that the mechanisms responsible for antibody induction differed between these forms of immunization. In contrast to the line 1 and EMT6 tumours, which are of BALB/c origin, OVA- or PSA-producing B16 melanoma cells, which are of C57BL/6 origin, failed to elicit antibody production. This was not the result of strain differences, as a similar finding was observed when the tumours were grown in (BALB/c x C57BL/6)F1 mice, but appeared to be caused by intrinsic differences in the tumours. Furthermore, co-injection of both B16/OVA and line 1 tumours resulted in production of anti-OVA antibody, indicating that B16 tumours were not immunosuppressive, but instead line 1 tumours appear to exert an adjuvant effect.

Adjuvants, Immunologic↗
PubMed2001

Root elongation against a constant force: experiment with a computerized feedback-controlled device.

Axial force was applied to the root tip of corn (Zea mays L. cv. Merit) seedlings using a computerized, feedback-controlled mechanical device. The system's feedback capability allowed continuous control of a constant tip load, and the attached displacement transducer provided the time course of root elongation. Loads up to 7.5 g decreased the root elongation rate by 0.13 mm h-1 g-1, but loads 7.5 to 17.5 g decreased the growth rate by only 0.04 mm h-1 g-1. Loads higher than 18 g stopped root elongation completely. Measurement of the cross-sectional areas of the root tips indicated that the 18 g load had applied about 0.98 MPa of axial pressure to the root, thereby exceeding the root's ability to respond with increased turgor pressure. Recorded time-lapse images of loaded roots showed that radial thickening (swelling) occurred behind the root cap, whose cross-sectional area increased with tip load.

Biophysical Phenomena↗
PubMed2001

An insight into cell elasticity and load-bearing ability. Measurement and theory.

We have studied the elasticity and load bearing ability of plant tissue at the cellular level, using onion (Allium cepa) epidermal cells. The Young's modulus and Poisson's ratio of the cells were obtained by loading a tensile force on onion epidermal peels of different turgor pressures, and measuring the elongation and the lateral contraction of the peels. The Young's moduli and the Poisson's ratios ranged from 3.5 to 8.0 MPa and 0.18 to 0.30, respectively. To determine the effects of cell elasticity and turgor pressure on the cell's ability to bear load, we loaded a small glass ball onto a cell and measured the projected contact area between the ball and the cell. Unlike previous studies, we considered the cell as a whole entity, and utilized the Boussinesq's solution to derive the relevant equations that related the elastic parameters and cell deformation. For cells with a turgor pressure > or = 0.34 MPa, the predicted contact area agreed well with the measured area. The equations could also predict cell turgor pressure with a deviation from the measured value of 0.01 MPa. This study gives strong support to ball tonometry, a new method of measuring cell turgor pressure.

Allium↗
PubMed2001

[Analysis of toxic organic compounds in MGP-Wastewater and investigation of Wastewater's general characteristics].

A full-scale investigation and analysis of MGP(Manufacture Gas from Petroleum)-Wastewater was carried out in this study. It's the first time that this paper publicizes the wastewater's general data, pretreatment method of GC/MS analysis and compositions of toxic organic compounds. The concentrtion of wastewater's CODCg, BOD5, phenolic, N-NH4+ and extractive-organic is: 400 mg.L(-1)-600 mg.L-1, 60 mg.L(-1)-80 mg.L-1, 20 mg.L(-1)-30 mg.L-1, 60 mg.L(-1)-80 mg.L-1 and 170 mg.L(-1)-200 mg.L-1 respectively. There are 79 kinds of aromatic compounds were detected by GC/MS, the total concentration of influent and effluent is 140.79 mg.L-1 and 129.11 mg.L-1 respectively. The data approved that MGP-wastewater is toxic and difficult for bio-treatment.

Gas Chromatography-Mass Spectrometry↗
PubMed2001

Genotyping and preparation of the recombinant nucleocapsid protein antigen of hantavirus.

OBJECTIVE: To identify new recombinant antigens with potential for diagnosis of hemorrhagic fever with renal syndrome (HFRS) and establish reverse transcription-polymerase chain reaction-restriction fragments length polymorphism (RT-PCR-RFLP) for genotyping of hantavirus. METHODS: One group of primers was used to clone the full-length S genome segment and the partial S genome segment of the N-terminal. The two cloned genes were both fusionally expressed and non-fusionally expressed in the T7 system. The other group of primers was used to establish a RT-PCR method to detect RNAs in 37 virus isolates, 2 positive standard virus strains of hantavirus and 5 negative controls. The method for typing RFLP was set up by digesting the PCR products of 20 virus isolates with Ras I and Hind III. RESULTS: The non-fusionally expressed products with a working concentration of 1:10,000 by chapping enzyme-linked immunosorbent assay (cELISA), presented good biological activity though yields were lower than that of the fusionally expressed products. The specific component of the hantavirus genome (299 bp or 577 bp) was seen in all viral samples. The genotyping of hantavirus showed that 9 out of the total were Hantann (HTN) viruses, 8 were seoul (SEO) viruses and 3 were not determined. CONCLUSIONS: The good working titrer of expressed recombinant antigen showed that it has the potential to replace the natural antigen for detecting hantavirus antibodies. On comparison with cELISA, the detection rates for these two methods were 100% and 84.6%, and the coincidence rate was 84.6%. The former had a 15.4% higher sensitivity than the latter. The typing efficiency of RT-PCR-RFLP and sero-typing method was 85% (17/20) and 55% (11/20), respectively, showing that the former was 30% higher than the latter, while their results were highly consistent.

Antibodies, Viral↗
PubMed2001

[Evaluation on comprehensive benefits of different regulation models of agroforestry ecosystem in snail river beach].

The economic, ecological, social and comprehensive benefits of different regulation models of agroforestry ecosystem in Nangeng river beach were evaluated by AHP. The results showed that agroforestry ecosystem was significantly superior to reed(Phragmites communis) system. Different regulation models of agroforestry ecosystem had different benefits. The sheet-thinning model had the highest economic, social, and comprehensive benefits, and it was the optimal regulation model. For all thinning models, the key approach to further raise benefits was to choose some intercrop variations, which had a high economic value, especially a high ratio of output to input. For no-thinning model, keeping on intercropping was the effective measure to raise the social and comprehensive benefits.

Ecosystem↗
PubMed2001

[Relationship between atmospheric temperature and growth characteristics of main edible grapes in south China].

The study shows that there existed a significant relationship between the new branch growth of grapes and temperature, especially effective accumulate temperature. Kyoho had the fastest new branch growth rate among all varieties, which was 0.43433 cm in length with raising 10 degrees C while effective accumulate temperature was over 190.68 degrees C. Mixiangbao had the slowest new branch growth rate, which was 0.17150 cm in length with raising 10 degrees C while effective accumulate temperature was over 367.19 degrees C. The economic properties and quality in variety character were researched by fuzzy valuation. The results showed that Kyoho, Jingya, Fujiminori, Mixiangbao, and Longbao were worthy of spreading, while Zizhenxiang would be limited in production, and Wase takasumi and Heifeng should be eliminated through selection.

China↗
PubMed2001

[Characteristics of nitrobenzene containing wastewater catalytic oxidation degradation by Fenton reagent].

Through the alteration of the concentration of catalyst and oxidant, the rulers and dynamics of nitrobenzene oxidized by Fenton reagent in different concentrations were studied. The correlativity of the reaction time and relatively remain nitrobenzene was analyzed by the unitary linear regress equation. The result of the analysis proves that the coefficient was over the critical constant. The oxidation of nitrobenzene by Fenton reagent was in conformity with first-order dynamics model and the reaction rate constant was got at the same time. The idea, using the complex of Fe as the catalyst replacing Fe2+ in the Fenton Reaction, not only got a higher reaction velocity and efficiency, but also had a distinct exclusive to the degradation of nitrobenzene. The remove velocity of nitrobenzene was improved from 17.48 mg/(L.min) to 71.22 mg/(L.min), the remove rate in 5 minutes was from 9.74% to 91.79%. The nonhomogeneous catalyst made by the artificial zeolite with Fe-complex adsorbed had the same catalyzing behavior. In addition, ultraviolet radiation can also improves the Fenton reaction to some degree. These research works could demonstrate the good application potentiality of Fenton reagent in treating wastewater.

Catalysis↗
PubMed2001

[Comprehensive evaluation on the effect of chemical regulation agent on rice injured by insufficient illumination during its heading-filling period].

Main indexes of rice injury by insufficient illumination (II) were selected through Gray Relation, and the effect of regulation agent on rice injured by II at different stages during heading-filling period was analyzed using Gradation Analysis and Fuzzy Comprehensive Evaluation. The results showed that the percentage of filled-grain, net assimilation rate and root activity were the top three indexes subject to injury. Application of chemical regulation agent when the injury occurred 6-20 days after heading had the best effect, with a degree of subordinacy of 0.7869.

Agrochemicals↗
PubMed2000

Murine pro-B cells require IL-7 and its receptor complex to up-regulate IL-7R alpha, terminal deoxynucleotidyltransferase, and c mu expression.

Phenotypic analysis of bone marrow cells from IL-7 knockout (KO) mice revealed that B cell development is blocked precisely at the transition between pro-B cells and pre-B cells. In contrast, the generation of pre-pro-B cells and pro-B cells appeared to be normal, as judged by total cell numbers, proliferative indexes, D-JH and V-DJH gene rearrangements, and mRNA for recombinase-activating gene-1 (RAG-1), RAG-2, TdT, Ig mu, lambda 5, and VpreB. However, upon closer inspection, several abnormalities in pro-B cell development were identified that could be corrected by injection of rIL-7 in vivo. These included the absence of the subset of late pro-B cells that initiates cmu expression for pre-B cell Ag receptor (BCR) formation, and the failure of pro-B cells to up-regulate TdT and the IL-7R alpha (but not the common gamma-chain) chain. Similar defects were present in common gamma-chain and Jak3 KO mice, but not in lambda 5 or (excluding cytoplasmic Ig mu heavy chain (c mu)) RAG-1 KO mice, all of which also arrest at the late pro-B cell stage. Consequently, up-regulation of TdT and IL-7R alpha expression requires signaling through the high affinity IL-7R, but does not require cmu expression or a functional pre-BCR. Taken together, these results suggest that IL-7 and its receptor complex are essential for 1) up-regulating the expression of TdT and IL-7R alpha, 2) initiating the production of cmu and 3) promoting the formation of a functional pre-BCR in/on pro-B cells. These key events, in turn, appear to be prerequisite both for differentiation of pro-B cells to pre-B cells and for proliferation of these cell subsets upon continued stimulation with IL-7.

Animals↗
PubMed2000

The influence of modified purine bases on the stability of parallel DNA.

The stability of the parallel-stranded (ps) DNA duplexes is increased when the dA-residues are replaced by the 7-substituted 7-deaza-2'-deoxyadenosine derivatives 3a,b or the dG-residues by the 8-aza-7-deazapurine 2'-deoxynucleosides 6 and 7a,b. Also the N-7-glycosylated adenine 5 forms stable base pairs in ps-DNA while it destabilizes oligonucleotide duplexes with antiparallel chain orientation. The presence of a 2-amino group as in compound 4b is critical for the DNA-structure, leading to a much greater destabilization of the ps-hybrids than of aps-DNA.

Base Sequence↗
PubMed2000

Ball tonometry: a rapid, nondestructive method for measuring cell turgor pressure in thin-walled plant cells.

In this article we describe a new method for the determination of turgor pressures in living plant cells. Based on the treatment of growing plant cells as thin-walled pressure vessels, we find that pressures can be accurately determined by observing and measuring the area of the contact patch formed when a spherical glass probe is lowered onto the cell surface with a known force. Within the limits we have described, we can show that the load (determined by precalibration of the device) divided by the projected area of the contact patch (determined by video microscopy) provides a direct, rapid, and accurate measure of the internal turgor pressure of the cell. We demonstrate, by parallel measurements with the pressure probe, that our method yields pressure data that are consistent with those from the pressure probe. Also, by incubating target tissues in stepped concentrations of mannitol to incrementally reduce the turgor pressure, we show that the pressures measured by tonometry accurately reflect the predicted changes from the osmotic potential of the bathing medium. The advantages of this new method over the pressure probe are considerable, however, in that we can move rapidly from cell to cell, taking measurements every 20 s. In addition, the nondestructive nature of the method means that we can return to the same cell repeatedly for periodic pressure measurements. The limitations of the method lie in the fact that it is suitable only for superficial cells that are directly accessible to the probe and to cells that are relatively thin walled and not heavily decorated with surface features. It is also not suitable for measuring pressures in flaccid cells.

Cell Physiological Phenomena↗
PubMed2000

Analysis of the disulfide bonding pattern between domain sequences of recombinant prochymosin solubilized from inclusion bodies.

Prochymosin contains three disulfide bonds linking Cys45 to Cys50, Cys206 to Cys210, and Cys250 to Cys283. To analyze the disulfide bonding pattern between domain sequences in the recombinant prochymosin molecule solubilized from inclusion bodies by 8 M urea (designated as solubilized prochymosin), a simple peptide mapping method was established. This process consists of thiol alkylation, cleavage with cyanogen bromide, diagonal electrophoresis on polyacrylamide gel, and N-terminal sequencing. By using this procedure it was found that Cys45 and Cys50 located in the N-terminal domain are not mispaired with the cysteine residues, located in the C-terminal domain, in the solubilized wild-type prochymosin and its mutants. This result implies that Cys45 and Cys50, the partners of a native disulfide, are restricted in some ordered structures existing in inclusion bodies and remaining after solubilization. These native structural elements act as folding nuclei to initiate and facilitate correct refolding. The strategy of preserving the native-like structures including native disulfide in the solubilized inclusion bodies to enhance renaturation efficiency may be applicable to other recombinant proteins.

Chymosin↗
PubMed2000

Chaperone-mediated refolding of recombinant prochymosin.

It has been verified that prochymosin is characterized by a two-stage refolding: dilution of unfolded protein into pH 11 buffer followed by neutralization at pH 8; the high-pH step is indispensable. Here we demonstrate that one-stage refolding around pH 8 can be achieved when GroE or 10-fold molar excess (rather than catalytic concentration) of protein disulfide isomerase (PDI) over prochymosin is present. The helping effect varies with the oxidation states of prochymosin. GroE and PDI increase the reactivation of the unfolded, partially reduced and the unfolded, oxidized prochymosin from 5% to 40% and from 50% to 100%, respectively. For the unfolded and fully reduced prochymosin, GroE does not have a positive effect, whereas PDI promotes renaturation from 2% to 28%. Based on our previous and present observations, we propose that at pH 8 there may be two kinds of incorrect interactions within and between prochymosin polypeptides leading to unproductive pathways: one prevents disulfide rearrangement, which can be avoided by high pH; the other interferes with acquisition of native conformation, which can be relieved by GroE and PDI.

Animals↗