Response-surface analysis for the inhibition toxicity of benzene derivatives to yeast Saccharomyces cerevisiae.
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Algorithms↗
Biomedical subjects
S Han
Publications and source records attributed to S Han.
Comparative inhibition and quantitative structure-activity relationships (QSARs) of substituted phenols to germination rate of Cucumis sativus.
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Cucumis sativus↗
Mechanism-based quantitative structure-phytotoxicity relationships comparative inhibition of substituted phenols on root elongation of Cucumis sativus.
Phytotoxicity of selected substituted phenols to Cucumis sativus (log1/RC50, root elongation half inhibition concentration [mol/L] in logarithmic form) was determined by using a root elongation inhibition method and quantitative structure-activity relationships (QSARs) were developed. Hydrophobicity, described by 1-octanol/water partition coefficient in logarithmic form (log Kow) and electronic effect (characterized by the energy of the lowest unoccupied orbital, Elumo) proved to contribute mainly to the phytotoxicity of phenols in this study. Log Kow was used as a probe to classify the tested chemicals into subsets according to the modes of toxic action. The result indicated that the substituted phenols fell into two classes in general: narcotic phenols and bioreactive phenols. Most phenols elicited their toxic response via a polar narcosis mechanism and an excellent log Kow-dependent QSAR was developed (log1/RC50 = 0.94 log Kow + 2.04, n = 22, r2adj = 0.89). Selected phenols with bioreactive substructures exhibited elevated bioreactive toxicity and a strong Elumo-dependent correlation was achieved (log1/RC50 = -0.91 Elumo + 2.73, n = 6, r2adj = 0.81). This implied that their reactive toxicity involved mainly their in vivo electrophilic reactions. In an effort to model all chemicals without regard to their mechanisms, a highly predictive response-surface was developed with the phytotoxicity, hydrophobicity, and electrophilic reactivity (log1/RC50 = 0.66 log Kow - 0.57 Elumo + 2.31, n = 28, r2adj = 0.88).
Biological Availability↗
Trace analysis of dissolved polychlorinated organic compounds in the water of the Yangtse River (Nanjing, China).
Eighteen organochlorine contaminants from the water samples of the Yangtse River have been qualitatively and quantitatively analyzed. The analysis of polychlorinated organic compounds (PCOCs) extracted by C18 Solid Phase Extract (SPE) was performed using HP6890 gas chromatograph coupled by ECD detector. The analytical results demonstrate that the analytical methods are reliable based on the fact that most of the recoveries for the targeted compounds are 60-90%. Most of the concerned contaminants, i.e. chlorinated pesticides and PCBs were found in the water samples of the Yangtse River, but their concentration was very low, <2.97 ng l(-1), which is far less than 1 microg l(-1)--the standard of drinking water of China. It is apparent that the PCOCs were in high concentration during the dry season, and in low concentration during the rainy season. The situation of PCOCs contamination in the water of the Yangtse River in 1999 was greatly improved in comparison with 10 years ago.
China↗
Spectrally resolved velocity exchange spectroscopy of two-phase flow.
The Velocity EXchange SpectroscopY (VEXSY) technique, which provides a means to correlate macroscopic molecular displacements measured during two intervals separated by a variable mixing period, has been applied for the first time to a system of two-phase flow. The chemical shift difference between water and methyl protons has been exploited to simultaneously determine the probability of displacements, or propagator, of both components in a water/silicone oil mixture flowing through a glass bead pack. The joint two-time probability densities as well as the conditional probabilities of velocities show a clearly distinct dispersion behaviour of both fluids which is a consequence of the different wetting properties of the fluids with respect to the glass surface of the bead pack.
Journal Article↗
Biodegradable polymer-based interleukin-12 gene delivery: role of induced cytokines, tumor infiltrating cells and nitric oxide in anti-tumor activity.
The objective of this study was to investigate the role of induced cytokines, tumor infiltrating cells and nitric oxide (NO) in anti-tumor activity upon intratumoral injection of free and condensed plasmid DNA encoding murine interleukin-12 (pmIL-12) into BALB/c mice bearing subcutaneous tumors. Poly[alpha-(4-aminobutyl)-L-glycolic acid] (PAGA) was used for complex formation with pmIL-12 in presence of 5% (w/v) glucose. Upon characterization, PAGA/pmIL-12 (3/1, +/-) complexes were found to be most effective in gene transfer and were used consistently throughout this study. The levels of mIL-12 p70 and induced cytokines were determined by ELISA in the supernatant of the cultured tumors of the CT-26 subcutaneous tumor bearing BALB/c female mice 48 h after intratumoral injection of PAGA/pmIL-12 complexes and naked pmIL-12. The levels of IL-12, IFN-gamma, TNF-alpha and NO were higher for the PAGA/pmIL-12 complexes than those for the naked pmIL-12, PAGA alone and 5% glucose injected groups. The relative presence of natural killer (NK) cells, CD4(+) T cells, and antigen presenting cells, such as macrophages and dendritic cells determined using immunohistochemistry was higher for PAGA/pmIL-12 complexes compared with naked pmIL-12. The presence of CMV promoter in plasmid encoding IL-12 cDNAs did not induce any type I interferon response. There was a significant improvement in the survival rate and the inhibition of tumor growth after repeated injections of PAGA/pmIL-12 complexes.
Adenocarcinoma↗
Agricultural machinery safety alert system using ultrasonic sensors.
This article introduces a conceptual safety alert system using ultrasonic sensors. The safety alert system was designed to detect moving objects in the vicinity of agricultural machinery. This system uses two ultrasonic sensors to detect the distances between the sensors and the moving object and a position detection algorithm to determine the moving object's position relative to the machinery. A stationary test bench was built to prove the concept of the safety sensing system. Validation tests in an outdoor environment indicated that the conceptual safety alert system was capable of detecting the position of a moving object in the vicinity of agricultural machinery in real time, and generating a timely warning signal to raise the attention of the operator for ensuring safe operations. This result proved that the conceptual system has tremendous potential for agricultural machinery applications.
Accidents, Occupational↗
Molecular characteristics of non-small cell lung cancer.
We used hierarchical clustering to examine gene expression profiles generated by serial analysis of gene expression (SAGE) in a total of nine normal lung epithelial cells and non-small cell lung cancers. Separation of normal and tumor, as well as histopathological subtypes, was evident by using the 3,921 most abundant transcript tags. This distinction remained when only 115 highly differentially expressed tags were used. Furthermore, these 115 transcript tags clustered into groups suggestive of the unique biological and pathological features of the different tissues examined. Adenocarcinomas were characterized by high-level expression of small airway-associated or immunologically related proteins, whereas squamous cell carcinomas overexpressed genes involved in cellular detoxification or antioxidation. The messages of two p53-regulated genes, p21(WAF1/CIP1) and 14-3-3final sigma, were consistently underexpressed in the adenocarcinomas, suggesting that the p53 pathway itself might be compromised in this cancer type. Gene expression patterns observed by SAGE were consistent with results obtained by quantitative real-time PCR or cDNA array analyses by using a total of 43 lung tumor and normal samples. Thus, although derived from only a few tissue libraries, gene expression profiles obtained by using SAGE most likely represent an unbiased yet distinctive molecular signature for the most common forms of human lung cancer.
Base Sequence↗
4-Aminopiperidine ureas as potent selective agonists of the human beta(3)-adrenergic receptor.
The preparation and structure-activity relationships (SARs) of potent agonists of the human beta(3)-adrenergic receptor (AR) derived from a 4-aminopiperidine scaffold are described. Examples combine human beta(3)-AR potency with selectivity over human beta(1)-AR and/or human beta(2)-AR agonism. Compound 29s was identified as a potent (EC(50)=1nM) and selective (greater than 400-fold over beta(1)- with no beta(2)-AR agonism) full beta(3)-AR agonist with in vivo activity in a transgenic mouse model of thermogenesis.
Adrenergic beta-3 Receptor Agonists↗
A diverse family of GPCRs expressed in specific subsets of nociceptive sensory neurons.
In vertebrates, peripheral chemosensory neurons express large families of G protein-coupled receptors (GPCRs), reflecting the diversity and specificity of stimuli they detect. However, somatosensory neurons, which respond to chemical, thermal, or mechanical stimuli, are more broadly tuned. Here we describe a family of approximately 50 GPCRs related to Mas1, called mrgs, a subset of which is expressed in specific subpopulations of sensory neurons that detect painful stimuli. The expression patterns of mrgs thus reveal an unexpected degree of molecular diversity among nociceptive neurons. Some of these receptors can be specifically activated in heterologous cells by RFamide neuropeptides such as NPFF and NPAF, which are analgesic in vivo. Thus, mrgs may regulate nociceptor function and/or development, including the sensation or modulation of pain.
Amino Acid Sequence↗
Application of the polysilicone fullerene coating for solid-phase microextraction in the determination of semi-volatile compounds.
Solid-phase microextraction using polysilicone fullerene (PF) coating has been applied for the determination of semi-volatile compounds. Detection limits at the 10 ng l(-1) to approximately microg l(-1) level were achieved using flame ionization detection. A wide linear range was obtained with precision below 7% relative standard deviation. Parameters that affect the extraction process were investigated, which included sampling time, desorption time, sampling temperature, and salting out effect. Compared to the non-polar commercial polydimethylsiloxane (PDMS) coating, the PF coating has higher extraction efficiency, better selectivity and greater sensitivity for aromatic compounds. The experimental results revealed the thermal stability and life span are superior to commercially available PDMS. The PF coating has been demonstrated to possess planarity molecular recognition. The theoretical study confirmed that quantification is feasible under non-equilibrium conditions by use of the PF coating.
Reproducibility of Results↗
Time-resolved measurement of dissipation-induced decoherence in a Josephson junction.
We determined the dissipation-induced decoherence time (DIDT) of a superconducting Josephson tunnel junction by time-resolved measurements of its escape dynamics. Double-exponential behavior of the time-dependent escape probability was observed, suggesting the occurrence of a two-level decay-tunneling process in which energy relaxation from the excited to the ground level significantly affects the escape dynamics of the system. The observation of temporal double-exponential dependence enables direct measurements of the DIDT, a property critical to the study of quantum dynamics and the realization of macroscopic quantum coherence and quantum computing. We found that the DIDT was tau(d) > 11 micros at T = 0.55 K, demonstrating good prospects for implementing quantum computing with Josephson devices.
Journal Article↗
Notch1 confers a resistance to glucocorticoid-induced apoptosis on developing thymocytes by down-regulating SRG3 expression.
We previously have reported that SRG3 is required for glucocorticoid (GC)-induced apoptosis in the S49.1 thymoma cell line. Activation of Notch1 was shown to induce GC resistance in thymocytes. However, the specific downstream target of Notch1 that confers GC resistance on thymocytes is currently unknown. We found that the expression level of SRG3 was critical in determining GC sensitivity in developing thymocytes. The expression of SRG3 also was down-regulated by the activated form of Notch1 (NotchIC). The promoter activity of the SRG3 gene also was down-regulated by NotchIC. Expression of transgenic SRG3 resulted in the restoration of GC sensitivity in thymocytes expressing transgenic Notch1. These results suggest that SRG3 is the downstream target of Notch1 in regulating GC sensitivity of thymocytes.
Animals↗
Cell type specific and glucose responsive expression of interleukin-4 by using insulin promoter and water soluble lipopolymer.
For gene therapy, tissue targeting of gene delivery systems is required for the maximum efficiency. In this study, we constructed pRIP-IL4 in which the expression of interleukin-4 (IL-4) was driven by the rat insulin promoter. WSLP-pRIP-IL4 complex was characterized by pancreas beta-cell specific and glucose responsive expression of IL-4. pRIP-IL4 was completely retarded at a 6:1 or higher N/P (nitrogen atom of WSLP/phosphate of plasmid) ratio in 1% agarose gel. In addition, WSLP protected plasmid DNA from DNase I for more than 1 h. In cytotoxicity assay, WSLP showed less cytotoxicity than PEI (25000 Da) to mouse insulinoma (MIN6) cells. ELISA showed that pRIP-IL4 expressed much higher levels of IL-4 in MIN6 cells than in NIH3T3 cells. The expression level of IL-4 by pRIP-IL4 increased with increasing concentration of glucose. Also, IL-4 was expressed in a dose-dependent manner. This WSLP-pRIP-IL4 system will be useful in the development of a pancreas specific expression system for the prevention of diabetes without systemic side effects.
Animals↗
A spectrophotometric assay of arginase.
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Arginase↗
Peripheral T cells become sensitive to glucocorticoid- and stress-induced apoptosis in transgenic mice overexpressing SRG3.
Immature double-positive thymocytes are sensitive to glucocorticoid (GC)-induced apoptosis, whereas mature single-positive T cells are relatively resistant. Thymocytes seem to acquire resistance to GCs during differentiation into mature single-positive thymocytes. However, detailed knowledge concerning what determines the sensitivity of thymocytes to GCs and how GC sensitivity is regulated in thymocytes during development is lacking. We have previously reported that the murine SRG3 gene (for SWI3-related gene) is required for GC-induced apoptosis in a thymoma cell line. Herein, we provide results suggesting that the expression level of SRG3 protein determines the GC sensitivity of T cells in mice. SRG3 associates with the GC receptor in the thymus, but rarely in the periphery. Transgenic overexpression of the SRG3 protein in peripheral T cells induces the formation of the complex and renders the cells sensitive to GC-induced apoptosis. Our results also show that blocking the formation of the SRG3-GC receptor complex with a dominant negative mutant form of SRG3 decreases GC sensitivity in thymoma cells. In addition, mice overexpressing the SRG3 protein appear to be much more susceptible to stress-induced deletion of peripheral T cells than normal mice, which may result in an immunosuppressive state in an animal.
Animals↗
Cytologic evaluation of cyclin D1 expression in primary breast carcinoma.
BACKGROUND: Preoperative assessment of the biologic characteristics of primary breast carcinoma is important because neoadjuvant medical therapy is being used increasingly. In the current study, the authors attempted to evaluate the validity of cyclin D1 assay in fine-needle aspiration (FNA) samples from patients with primary breast carcinoma. METHODS: FNA samples were obtained prior to therapy and multiple slides were stored at -80 degrees C for subsequent immunocytochemical analysis (ICA). ICA for cyclin D1 protein was performed on FNA samples from 51 breast carcinoma patients and 20 samples from patients with benign breast disease. In 45 breast carcinoma patients who had undergone surgery, sections were taken from paraffin blocks and stained by ICA for cyclin D1 validation. Possible correlations between cyclin D1 expression in the FNA samples and the biologic data of the patients also were analyzed. RESULTS: Cyclin D1 expression was detected in 37 FNA samples from 51 breast carcinomas (72.5%) whereas expression of cyclin D1 was detected in 8 FNA samples from 20 patients with benign breast disease (40%). In histologic sections after surgery, 26 cases of breast carcinoma (65%) showed a positive reaction to cyclin D1. Concordance for the presence of cyclin D1 between FNA samples and histologic samples was 75%. Cyclin D1 expression was high in patients with the tumors that expressed estrogen receptor (ER) (30 of 34 vs. 5 of 11; P = 0.028) and progesterone receptor (PR) (33 of 38 vs. 2 of 7; P = 0.007). There was no significant relation found between cyclin D1 expression and tumor size or lymph node metastasis. Cyclin D1 expression within invasive ductal carcinoma was observed in > 80% of low or intermediate nuclear grade tumors but its expression decreased to 61.5% (8 of 13 cases) in tumors with high nuclear grade (P = 0.023). All 14 breast carcinomas in which the S-phase fraction was </= 15% showed a high degree of cyclin D1 expression whereas 4 of 6 tumors (66.7%) in which the S-phase fraction was > 15% showed cyclin D1 expression. Cyclin D1 expression was found to be correlated inversely with proliferative activity in breast carcinoma (P = 0.023). CONCLUSIONS: The results of the current study show that cyclin D1 expression can be measured by ICA in FNA samples with reasonable concordance with the results of histologic section. Cyclin D1 expression was found to be associated with ER/PR status and cell differentiation. The results of the current study indicate that the measurement of novel molecular markers could be performed adequately in FNA samples as well as in histologic sections.
Adult↗
Reaction imaging with interferometry.
We analyze scattering into a double-slit interferometer with target-fragment recoil detection as a monitor of quantum correlation and entanglement in few-body reaction amplitudes. We thus investigate two-slit interference with which-way information as an enhancement to modern reaction-fragment detection. We briefly consider charged-particle scattering with recoil-ion detection from the point of view of quantum information.
Journal Article↗