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Biomedical subjects

Wei Cai

Publications and source records attributed to Wei Cai.

At least 37 records · Page 2Linked to original sources
PubMed2005

Effects of fructose-1,6-diphosphate on concentration of calcium and activities of sarcoplosnic Ca2+-ATPase in cardiomyocytes of Adriamycin-treated rats.

OBJECTIVE: To observe the effects of fructose-1,6-diphosphate (FDP) on serum levels of cardiac troponin I (cTnI) and creatine kinase-MB (CK-MB), as well as the concentration of calcium in cardiomyocytes (Myo[Ca(2+)]) and activity of sarcoplosnic Ca(2+)-ATPase (SRCa(2+)-ATPase) in Adriamycin (ADR)-treated rats. METHODS: Rats were intraperitoneally injected with ADR (2.5 mg/kg every other day for 6 times) and then with different dosages of FDP (every other day for twenty-one times). Bi-antibodies sandwich Enzyme linked immune absorption assay (ELISA) was performed to detect serum level of cTnI. CK-MB was detected by monoclonal antibody, Myo[Ca(2+)] was detected by fluorescent spectrophotometry and the activity of SRCa(2+)-ATPase was detected by inorganic phosphate method. RESULTS: FDP (300, 600, 1200 mg/kg) significantly reduced the serum levels of cTnI and CK-MB, while at the same time decreased calcium concentration and increased SRCa(2+)-ATPase activity in cardiomyocytes of ADR-treated rats (P<0.01). CONCLUSIONS: FDP might alleviate the cardiotoxic effects induced by ADR through decreasing calcium level as well as increasing SRCa(2+)-ATPase activity in cardiomyocytes.

Animals↗
PubMed2005

Yangxueqingnao particles inhibit rat vascular smooth muscle cell proliferation induced by lysophosphatidic acid.

OBJECTIVE: To observe the effect of Yangxueqingnao particles on rat vascular smooth muscle cell (VSMC) proliferation induced by lysophosphatidic acid (LPA). METHODS: The amount of (3)H-TdR ((3)H-thymidine) admixed in cultured rat VSMC was measured and mitogen-activated protein kinase (MAPK) activity and lipid peroxidation end product malondialdehyde (MDA) content of the VSMC were assayed. RESULTS: 1x10(-9), 1x10(-8), 1x10(-7) mol/L LPA in a concentration dependent manner, induced the amount of (3)H-TdR admixed, MAP kinase activity, and MDA content of the cultured rat VSMC to increase. However, 5%, 10%, and 15% Yangxueqingnao serum preincubation resulted in a decrease of 23.0%, 42.0%, and 52.0% (P<0.01) respectively in the amount of (3)H-TdR admixed, a decline in VSMC MAP kinase activity of 13.9% (P<0.05), 29.6% (P<0.01), and 48.9% (P<0.01) respectively, and also, a decrease in MDA content of VSMC of 19.4%, 24.7%, and 43.2% (P<0.01) respectively, in the 1x10(-7) mol/L LPA-treated VSMC. CONCLUSIONS: LPA activates the proliferation and lipid peroxidation of VSMC in a concentration dependent manner. The LPA-induced VSMC proliferation is related to the activity of MAP kinases, enzymes involved in an intracellular signalling pathway. The results of the present study showed that Yangxueqingnao particles can effectively inhibit LPA-induced VSMC proliferation, MAP kinase activation, and reduce lipid peroxidative lesion.

Animals↗
PubMed2005

[The correlation between personal anxiety and dental fear among 1975 junior college students in southwest China].

OBJECTIVE: To reveal the correlation between personal anxiety (PA) and dental fear (DF) among the junior college students in Southwest China. METHODS: The Corah's questionnaire and personal anxiety measuring indicator (SAS) were conducted on 1 975 junior college students in Chengdu. The collected data was analyzed by Software SPSS 10. RESULTS: A correlation was found between DF and PA (chi2 = 3.97, P < 0.05). The score of DF was well related with the score of the 15 questions designed (r = 0.913, P = 0. 000). The side affections during dental treatment process had significant effects on DF (r = 0. 409, P = 0.000). CONCLUSION: A correlation was found between DF and PA among the junior college students in Southwest China.

Anxiety↗
PubMed2005

[Levels of common knowledge on common psychiatric disorders and therapeutic means taken in general population: effects of education level and living area].

OBJECTIVE: To investigate the differences in level of common knowledge toward common psychiatric disorders and means of therapy in general population, resulting from different education levels and living areas. METHODS: All 4,614 persons over 15 years of age recruited from general population in Zhejiang Province via stratified randomly sampling, were classified by education levels as illiteracy, primary school level, high school level, and college level. Each group was thus divided into two categories according to the person's living areas, ie urban and rural area. The level of common knowledge about psychosis and means of therapy were measured by a questionnaire administered to all subjects. RESULTS: The rate of knowledge of neurasthenic was the highest, reaching to 71.1%, then of knowledge of schizophrenia and depression, was 47.9% and 39.3% respectively, and the rate of knowledge of alcohol dependence, mania and obsessive-compulsive disorder was lower than 20%. The rate of knowledge of the 6 common psychiatric disorders was higher in people from urban area, than from rural areas. The rate of knowledge of common psychiatric disorders was increased correspondingly to the increase of the education level among the people residing at the same living area. The main means of therapy the people selected was western medicine and psychology, reaching at 24.0% and 34.8% respectively. There were significant differences among the people with different education levels but from the same living areas, and the people with lower education levels were likely to choose the therapy of western medicine, on the other hand, the people with higher education levels were tending to choose the therapy of psychology. CONCLUSION: The popularization of the knowledge and the education about mental health should be reinforced, as to improving the knowledge about mental health, choosing a correct means of therapy to the common psychiatric disorders and promoting the mental health status of the population.

Adolescent↗
PubMed2005

[Phase II randomized clinical trail of zoledronic acid in treating metastatic bone pain of malignancy].

BACKGROUND & OBJECTIVE: Bone metastases are the prevailing reason for pain in patients with malignancies, which seriously affect their life quality. Zoledronic acid, the third generation of bisphosphonates, can inhibit the activity of osteoclasts and relieve pain. This study was to evaluate the efficacy and safety of zoledronic acid in treating metastatic bone pain for patients with malignancies. METHODS: A multi-center, randomized, double-blind, and prospective trail was conducted. Patients with metastatic bone pain were randomized to receive zoledromic acid plus monnitol, or pamidronate plus monnitol as positive control. RESULTS: From Oct. 2003 to Oct. 2004, 216 patients with metastatic bone pain were randomized into 2 groups: 109 in zoledromic acid group, and 107 in pamidronate group. There was no significant difference in pain intensity (PI) between zoledromic acid group and pamidronate group before treatment (6.0+/-1.1 vs. 6.0+/-1.3, P=0.938), 7 days after treatment (3.7+/-1.99 vs. 4.1+/-2.0, P=0.119), and 14 days after treatment (3.2+/-2.0 vs. 3.7+/-2.4, P=0.129). The differences in complete response (CR) rate, partial response (PR) rate, and total response rate between the 2 groups were not significant (10.4% vs. 9.5%, 69.8% vs. 69.5%, 88.7% vs. 85.7%, P>0.05). Time to CR was significantly shorter in zoledromic acid group than in pamidronate group [(7.0+/-2.2) days vs. (9.5+/-2.6) days, P=0.033]; the differences in time to PR, duration of CR, and duration of PR between the 2 groups were not significant [(4.9+/-2.6) days vs. (5.0+/-2.5) days, P=0.908; (13.2+/-1.80) days vs. (14.0+/-0.0) days, P=0.155; and (13.4+/-1.9) days vs. (12.8+/-2.8) days, P=0.127]. The main adverse events were fever, nausea, vomiting, and general malaise. The occurrence and severity of adverse events were similar between the 2 groups. CONCLUSION: Zoledromic acid is effective and safe in treating metastatic bone pain of patients with malignancy, which is similar to pamidranate.

Adult↗
PubMed2004

Reconstruction of ancestral protein sequences and its applications.

BACKGROUND: Modern-day proteins were selected during long evolutionary history as descendants of ancient life forms. In silico reconstruction of such ancestral protein sequences facilitates our understanding of evolutionary processes, protein classification and biological function. Additionally, reconstructed ancestral protein sequences could serve to fill in sequence space thus aiding remote homology inference. RESULTS: We developed ANCESCON, a package for distance-based phylogenetic inference and reconstruction of ancestral protein sequences that takes into account the observed variation of evolutionary rates between positions that more precisely describes the evolution of protein families. To improve the accuracy of evolutionary distance estimation and ancestral sequence reconstruction, two approaches are proposed to estimate position-specific evolutionary rates. Comparisons show that at large evolutionary distances our method gives more accurate ancestral sequence reconstruction than PAML, PHYLIP and PAUP*. We apply the reconstructed ancestral sequences to homology inference and functional site prediction. We show that the usage of hypothetical ancestors together with the present day sequences improves profile-based sequence similarity searches; and that ancestral sequence reconstruction methods can be used to predict positions with functional specificity. CONCLUSIONS: As a computational tool to reconstruct ancestral protein sequences from a given multiple sequence alignment, ANCESCON shows high accuracy in tests and helps detection of remote homologs and prediction of functional sites. ANCESCON is freely available for non-commercial use. Pre-compiled versions for several platforms can be downloaded from ftp://iole.swmed.edu/pub/ANCESCON/.

Amino Acid Sequence↗
PubMed2004

Ab initio calculations in a uniform magnetic field using periodic supercells.

We present a formulation of ab initio electronic structure calculations in a finite magnetic field, which retains the simplicity and efficiency of techniques widely used in first principles molecular dynamics simulations, based on plane-wave basis sets and Fourier transforms. In addition we discuss results obtained with this method for the energy spectrum of interacting electrons in quantum wells, and for the electronic properties of dense fluid deuterium in a uniform magnetic field.

Journal Article↗
PubMed2004

Direct electrical detection of hybridization at DNA-modified silicon surfaces.

Electrochemical impedance spectroscopy was used to investigate the changes in interfacial electrical properties that arise when DNA-modified Si(111) surfaces are exposed to solution-phase DNA oligonucleotides with complementary and non-complementary sequences. The n- and p-type silicon(111) samples were covalently linked to DNA molecules via direct Si?C linkages without any intervening oxide layer. Exposure to solutions containing DNA oligonucleotides with the complementary sequence produced significant changes in both real and imaginary components of the electrical impedance, while exposure to DNA with non-complementary sequences generated negligible responses. These changes in electrical properties were corroborated with fluorescence measurements and were reproduced in multiple hybridization-denaturation cycles. The ability to detect DNA hybridization is strongly frequency-dependent. Modeling of the response and comparison of results on different silicon bulk doping shows that the sensitivity to DNA hybridization arises from DNA-induced changes in the resistance of the silicon substrate and the resistance of the molecular layers.

Biosensing Techniques↗
PubMed2004

Invasive cleavage reactions on DNA-modified diamond surfaces.

Recently developed DNA-modified diamond surfaces exhibit excellent chemical stability to high-temperature incubations in biological buffers. The stability of these surfaces is substantially greater than that of gold or silicon surfaces, using similar surface attachment chemistry. The DNA molecules attached to the diamond surfaces are accessible to enzymes and can be modified in surface enzymatic reactions. An important application of these surfaces is for surface invasive cleavage reactions, in which target DNA strands added to the solution may result in specific cleavage of surface-bound probe oligonucleotides, permitting analysis of single nucleotide polymorphisms (SNPs). Our previous work demonstrated the feasibility of performing such cleavage reactions on planar gold surfaces using PCR-amplified human genomic DNA as target. The sensitivity of detection in this earlier work was substantially limited by a lack of stability of the gold surface employed. In the present work, detection sensitivity is improved by a factor of approximately 100 (100 amole of DNA target compared with 10 fmole in the earlier work) by replacing the DNA-modified gold surface with a more stable DNA-modified diamond surface.

Apolipoproteins E↗
PubMed2004

Dynamic transitions from smooth to rough to twinning in dislocation motion.

The motion of dislocations in response to stress dictates the mechanical behaviour of materials. However, it is not yet possible to directly observe dislocation motion experimentally at the atomic level. Here, we present the first observations of the long-hypothesized kink-pair mechanism in action using atomistic simulations of dislocation motion in iron. In a striking deviation from the classical picture, dislocation motion at high strain rates becomes rough, resulting in spontaneous self-pinning and production of large quantities of debris. Then, at still higher strain rates, the dislocation stops abruptly and emits a twin plate that immediately takes over as the dominant mode of plastic deformation. These observations challenge the applicability of the Peierls threshold concept to the three-dimensional motion of screw dislocations at high strain rates, and suggest a new interpretation of plastic strength and microstructure of shocked metals.

Iron↗
PubMed2004

[Study on the molecular epidemiology of hantaviruse carried by hosts in northern suburb of Beijing].

OBJECTIVE: To investigate hantanvirus infection of captured rodents in Haidian district and Changping district of Beijing and to type hantavirus using molecular technique. METHODS: The captured mice were classified and the density of distribution was calculated. Reverse transcription-polymerase chain reaction (RT-PCR) technique was used to amplify the partial M fragnments of hantaviruse. Several representative positive samples were sequenced and analysed by ClustalX (5.0) and DNAClub software. RESULTS: A total of 414 animals were captured, among which Battus norvegicus was the dominant group. In Haidian district, the median infection rates with hantavirus were 13.14% in Battus norvegicus and 0 in Mus musculus Linnaeus. In Changping district, the average infection rates were 17.46% in Battus norvegicus and 3.57% in Mus musculus Linnaeus. Nucleotide sequences analysis showed that the virus detected all belonged to SEO-type. They clustered with Z37 virus and could be branched into 2 different subclades. CONCLUSION: The major hosts of hantavirus in Haidian and Changping district were Battus norvegicus and the epidemic strains in the two districts of Beijing were genotyped as SEO-type. Nucleotide sequence and deduced amino acid sequence from different rodents were highly homologous, while nucleotide mutation had also been observed. Further studies are required to explore the possible virus sequence mutation.

Animals↗
PubMed2003

Frequency-dependent electrical detection of protein binding events.

Frequency-dependent electrochemical impedance spectroscopy has been used to characterize the changes in electrical response that accompany specific binding of a protein to its substrate, using the biotin-avidin system as a model. Our results show that avidin, at concentrations in the nanomolar range, can be detected electrically in a completely label-free manner under conditions of zero average current flow and without the use of any auxiliary redox agents. Impedance measurements performed on biotin-modified surfaces of gold, glassy carbon, and silicon were obtained over a wide frequency range, from 5 mHz to 1 MHz. On each biotin-modified surface, binding of avidin is most easily detected at low frequencies, <1 Hz. Electrical circuit modeling of the interface was used to relate the frequency-dependent electrical response to the physical structure of the interface before and after avidin binding. Electrical measurements were correlated with measurements of protein binding using fluorescently labeled avidin.

Avidin↗
PubMed2003

Anomalous dislocation multiplication in FCC metals.

Direct atomistic simulations of dislocation multiplication in fcc aluminum reveal an unexpected mechanism, in which a Frank-Read source emits dislocations with Burgers vectors different from that of the source itself. The mechanism is traced to a spontaneous nucleation of partial dislocation loops within the stacking fault. Understanding and a quantitative description of this unusual process are achieved through the development of a continuum model for dislocation nucleation based on the coarse-grained dislocation dynamics approach and a minimal amount of atomistic input.

Journal Article↗
PubMed2003

Time-resolved polarization to extract coded information from early ballistic and snake signals through turbid media.

Time-resolved polarization is used to extract coded information buried within the multiple scattering profiles from the early ballistic and snake components as they pass through turbid media. By polarization analysis the depolarized diffusive component and the natural-light background are significantly reduced to enhance the signal-to-noise ratio of a coded pulse train. This procedure has the potential to improve optical wireless communication in cloudy environments.

Journal Article↗
PubMed2003

Normal value of resting energy expenditure in healthy neonates.

OBJECTIVE: We investigated the value of resting energy expenditure (REE) in healthy neonates and evaluated the impact factors on REE. METHODS: One hundred eighty healthy neonates (95 boys and 85 girls) with birth weights above 2500 g were measured by indirect calorimetry, and the effect of birth weight evaluated. Measured and predicted REEs were compared, and the effects of sex and delivery method on REE were examined in 154 newborn infants with birth weights of approximately 2500 to 4000 g. RESULTS: Birth weight had a significant effect on REE. There was a negative relation between REE and birth weight (r = -0.289). The REEs of newborn infants weighing more than 4000 g were statistically lower than those of infants weighing 2500 to 4000 g (44.5 +/- 5.9 versus 48.3 +/- 6.1 kcal x kg(-1) x d(-1), P = 0.01). The measured and predicted REEs of 154 newborn infants were 48.3 +/- 6.1 and 54.1 +/- 1.1 kcal x kg(-1) x d(-1), respectively. There was a significant difference between the two values. Sex and delivery methods had no effect on REE in healthy neonates. CONCLUSIONS: The value from the predicted equation is not suitable for neonatal energy supplementation in clinical practice. The normal REE value for healthy neonates with birth weights of 2500 to 4000 g is 48.3 +/- 6.1 kcal x kg(-1) x d(-1).

Birth Weight↗
PubMed2003

[Radioactivity of phosphorus implanted TiNi alloy].

Exposed to neutron flow, the phosphorus implanted TiNi alloy gets radioactive. This radioactive material is used in vascular stent for prevention and cure of restenosis. Phosphorus implantation is carried out in a plasma immerged ion implantation system, and the dose of phosphorus implantation is in the range of 2-10 x 10(17) cm-2. After ion implantation, the alloy is exposed to the slow neutron flow in a nuclear reactor, the dose of the slow neutron is 1.39-5.88 x 10(19) n/cm2. The radioactivity of the TiNi alloy was measured by liquid scintillation spectrometry and radio-chromic-film dosimetry. The result shows that whether the phosphorus is implanted or not, the TiNi alloy comes to be radioactive after exposure to neutron flow. Just after neutron irradiation, the radiation dose of phosphorus implanted TiNi alloy is about one hundred times higher than that of un-phosphorus implanted TiNi alloy. The radiation difference between phosphorus and un-phosphorus implanted alloy decreases as time elapses. Within three months after neutron irradiation, the average half-decay period of phosphorus implanted TiNi alloy is about 62 days. The radiation ray penetration of phosphorus implanted TiNi alloy is deeper than that of pure 32P; this is of benefit to making radiation uniformity between stent struts and reducing radiation grads beyond the edge of stent.

Alloys↗