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ABSTRACT: The rapid, accurate and sensitive determination of hydrogen peroxide (H(2)O(2)) is of great significance in the physiological, pathological and environmental fields. In this work, we have proposed a highly sensitive and selective amperometric biosensor for the detection of extracellular H(2)O(2) released from human breast cancer cells with the help of a sequence-specific peptide. Since the peptide immobilized on the electrode surface can specifically bind with horseradish peroxidase (HRP) in a favorable orientation, which then well promotes the catalytic activities of the immobilized enzyme toward the reaction of o-phenylenediamine and H(2)O(2), the proposed biosensor can detect H(2)O(2) in a wide linear range from 1.0×10(-7)M to 1.0×10(-4)M with a low detection limit of 3.0×10(-8)M. It can be also directly used to efficiently trace extracellular H(2)O(2) released from human breast cancer cells MCF-7. Furthermore, the reproducibility, stability and selectivity of the biosensor are also quite well compared with the previous report, so our biosensor might be potentially useful in physiological and pathological detection of H(2)O(2) in the future.
Biosensors & bioelectronics 10/2012; · 5.43 Impact Factor
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ABSTRACT: Herein we report a sensitive electrochemical biosensor for DNA detection by making use of exonuclease III and probe DNA functionalized gold nanoparticles. While probe DNA P1 modified on a gold electrode surface can self-hybridize into a stem-loop structure with an exonuclease III-resistant 3' overhang end, in the presence of target DNA, P1 may also hybridize with the target DNA to form a duplex region. Therefore, exonuclease III may selectively digest P1 from its 3'-hydroxyl termini until the duplex is fully consumed. Since a single target DNA can trigger exonuclease III digestion of numerous P1 strands, the first signal amplification is achieved. On the other hand, since the digested P1, exposing its complementary sequence to probe DNA P2, can further hybridize with P2 that has been previously modified on the surface of gold nanoparticles, many nanoparticles loaded with numerous DNA strands are immobilized onto the electrode surface. Consequently, large amount of electroactive molecules [Ru(NH(3))(6)](3+) can bind with the DNA strands to produce an intense electrochemical response as the second signal amplification. Based on the studies with cyclic voltammetry (CV) and chronocoulometry (CC) techniques, the proposed biosensor can sensitively detect specific target DNA at a picomolar level with high specificity.
Biosensors & bioelectronics 03/2012; 33(1):211-5. · 5.43 Impact Factor
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Huann-Sheng Chen,
Kenneth Portier,
Kaushik Ghosh,
Deepa Naishadham,
Hyune-Ju Kim, Li Zhu,
Linda W Pickle,
Martin Krapcho,
Steve Scoppa,
Ahmedin Jemal,
Eric J Feuer
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ABSTRACT: A study was undertaken to evaluate the temporal projection methods that are applied by the American Cancer Society to predict 4-year-ahead projections.
Cancer mortality data recorded in each year from 1969 through 2007 for the United States overall and for each state from the National Center for Health Statistics was obtained. Based on the mortality data through 2000, 2001, 2002, and 2003, Projections were made 4 years ahead to estimate the expected number of cancer deaths in 2004, 2005, 2006, 2007, respectively, in the United States and in each state, using 5 projection methods. These predictive estimates were compared to the observed number of deaths that occurred for all cancers combined and 47 cancer sites at the national level, and 21 cancer sites at the state level.
Among the models that were compared, the joinpoint regression model with modified Bayesian information criterion selection produced estimates that are closest to the actual number of deaths. Overall, results show the 4-year-ahead projection has larger error than 3-year-ahead projection of death counts when the same method is used. However, 4-year-ahead projection from the new method performed better than the 3-year-ahead projection from the current state-space method.
The Joinpoint method with modified Bayesian information criterion model has the smallest error of all the models considered for 4-year-ahead projection of cancer deaths to the current year for the United States overall and for each state. This method will be used by the American Cancer Society to project the number of cancer deaths starting in 2012.
Cancer 02/2012; 118(4):1091-9. · 4.77 Impact Factor
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Li Zhu,
Linda W Pickle,
Kaushik Ghosh,
Deepa Naishadham,
Kenneth Portier,
Huann-Sheng Chen,
Hyune-Ju Kim,
Zhaohui Zou,
James Cucinelli,
Betsy Kohler,
Brenda K Edwards,
Jessica King,
Eric J Feuer,
Ahmedin Jemal
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ABSTRACT: The current study was undertaken to evaluate the spatiotemporal projection models applied by the American Cancer Society to predict the number of new cancer cases.
Adaptations of a model that has been used since 2007 were evaluated. Modeling is conducted in 3 steps. In step I, ecologic predictors of spatiotemporal variation are used to estimate age-specific incidence counts for every county in the country, providing an estimate even in those areas that are missing data for specific years. Step II adjusts the step I estimates for reporting delays. In step III, the delay-adjusted predictions are projected 4 years ahead to the current calendar year. Adaptations of the original model include updating covariates and evaluating alternative projection methods. Residual analysis and evaluation of 5 temporal projection methods were conducted.
The differences between the spatiotemporal model-estimated case counts and the observed case counts for 2007 were < 1%. After delays in reporting of cases were considered, the difference was 2.5% for women and 3.3% for men. Residual analysis indicated no significant pattern that suggested the need for additional covariates. The vector autoregressive model was identified as the best temporal projection method.
The current spatiotemporal prediction model is adequate to provide reasonable estimates of case counts. To project the estimated case counts ahead 4 years, the vector autoregressive model is recommended to be the best temporal projection method for producing estimates closest to the observed case counts.
Cancer 02/2012; 118(4):1100-9. · 4.77 Impact Factor
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ABSTRACT: To develop an in situ PCR in combination with flow cytometry (ISPCR-FCM) for monitoring cholera toxin positive Vibrio cholerae.
In running this method, 4% paraformaldehyde was used to fix the Vibrio cholerae cells and 1 mg/mL lysozyme for 20 min to permeabilize the cells. Before the PCR thermal cycling, 2.5% glycerol was added into the PCR reaction mixture in order to protect the integrality of the cells.
A length of 1037bp DNA sequence was amplified, which is specific for the cholera toxin gene (ctxAB gene). Cells subjected to ISPCR showed the presences of ctxAB gene both in epifluorescence microscopy and in flow cytometric analysis. The specificity and sensitivity of the method were investigated. The sensitivity was relatively low (10(5) cells/mL), while the specificity was high.
We have successfully developed a new technique for detection of toxigenic Vibrio cholerae strains. Further study is needed to enhance its sensitivities. ISPCR-FCM shows a great promise in monitoring specific bacteria and their physiological states in environmental samples.
Biomedical and Environmental Sciences 03/2007; 20(1):64-9. · 1.35 Impact Factor
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Qing Chen,
Li-lan Zhang,
De-xian Yu,
Zhi-ai Yu,
Yi Liu,
Li-ping Zhang,
Zhi-feng Li,
Zhao-jun Duan,
Bin-hui Wang,
Xue-jun Wei, [......],
Jian-dong Li,
Ying-chun Dai,
Jun Nie,
Jun Long, Li Zhu,
Su-xia Sun,
Yong-yu Rui,
Ding-kang Zhang,
Shou-yi Yu,
Yun-de Hou
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ABSTRACT: To evaluate the safety of recombinant human interferon alpha-2b for nasal spray for the prevention of SARS and other upper respiratory viral infections.
Field epidemiologic evaluation was conducted, the design was randomized and had a synchronously parallel control group. In the study, the drugs were given for five days and all subjects were followed up for ten days.
During the period of using interferon, body temperature of the experimental group was normal compared to the control group. Experimental group had more influenza-like symptoms than the control group (P < 0.05), such as headache (4.83%-7.09%), dizziness (7.17%-11.63%), lassitude (8.55%-15.06%), muscular soreness (4.43%-7.09%), pharynx dryness (12.10%-17.85%), angina (6.25%-8.72%), abdominal pain (2.30%-5.50%) and diarrhea (2.45%-5.66%). Most of side effects reached their peak with in the first 3 days. Except for pharynx dryness, the incidences of all other side effects declined after completion of the use of the trial drug, and incidences of some symptoms in experimental group were lower than those of the control group. There were no significant differences in the symptoms of cough and expectoration between the experimental group and the control group. The incidence of exanthem in the control group was significantly higher than that in the experimental group. The side effect of bloody nasal mucus was not observed in experimental group, which had been reported by other authors in several volunteer studies.
Using recombinant human interferon alpha-2b for nasal spray could lead to some influenza-like symptoms, however, all those symptoms were mild , reversible, and relieved after completion of the use of the trial drug. No serious side effects were found during the period of following up. The authors conclude that the drug is safe.
Zhonghua shi yan he lin chuang bing du xue za zhi = Zhonghua shiyan he linchuang bingduxue zazhi = Chinese journal of experimental and clinical virology 10/2005; 19(3):211-5.
