Biomedical subjects

J Zeng

Publications and source records attributed to J Zeng.

At least 19 recordsLinked to original sources

PubMed2006

An N-methyl-D-aspartate receptor mediated large, low-frequency, spontaneous excitatory postsynaptic current in neonatal rat spinal dorsal horn neurons.

Examples of spontaneous oscillating neural activity contributing to both pathological and physiological states are abundant throughout the CNS. Here we report a spontaneous oscillating intermittent synaptic current located in lamina I of the neonatal rat spinal cord dorsal horn. The spontaneous oscillating intermittent synaptic current is characterized by its large amplitude, slow decay time, and low-frequency. We demonstrate that post-synaptic N-methyl-D-aspartate receptors (NMDARs) mediate the spontaneous oscillating intermittent synaptic current, as it is inhibited by magnesium, bath-applied d-2-amino-5-phosphonovalerate (APV), or intracellular MK-801. The NR2B subunit of the NMDAR appears important to this phenomenon, as the NR2B subunit selective NMDAR antagonist, alpha-(4-hydroxphenyl)-beta-methyl-4-benzyl-1-piperidineethanol tartrate (ifenprodil), also partially inhibited the spontaneous oscillating intermittent synaptic current. Inhibition of spontaneous glutamate release by the AMPA/kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) or the mu-opioid receptor agonist [D-Ala2, N-Me-Phe4, Gly5] enkephalin-ol (DAMGO) inhibited the spontaneous oscillating intermittent synaptic current frequency. Marked inhibition of spontaneous oscillating intermittent synaptic current frequency by tetrodotoxin (TTX), but not post-synaptic N-(2,6-dimethylphenylcarbamoylmethyl)triethylammonium bromide (QX-314), suggests that the glutamate release important to the spontaneous oscillating intermittent synaptic current is dependent on active neural processes. Conversely, increasing dorsal horn synaptic glutamate release by GABAA or glycine inhibition increased spontaneous oscillating intermittent synaptic current frequency. Moreover, inhibiting glutamate transporters with threo-beta-benzyloxyaspartic acid (DL-TBOA) increased spontaneous oscillating intermittent synaptic current frequency and decay time. A possible functional role of this spontaneous NMDAR-mediated excitatory postsynaptic current in modulating nociceptive transmission within the spinal cord is discussed.

Adrenergic alpha-Antagonists↗

PubMed2006

Characterization of HLA-B5516, -B1313, -B9512, and -DRB11457 alleles identified in a southwest Chinese population.

The human leukocyte antigen (HLA)-B*5516 allele differs from the B*5502 by a single 97 T --> C substitution (His to Tyr at position 33) in exon 2. The B*1313 allele results from 419 T --> A and 420 A --> C substitutions, encoding a Leu to Tyr substitution at 140 in exon 2 of the B*1301 allele. The B*9512 allele differs from B*1502 by a single 360 G --> C substitution (Gln to His at 120) in exon 3. The DRB1*1457 allele appears to be a hybrid molecule generated by recombination between the DRB1*13 and DRB1*14 alleles. The serological equivalents of these new alleles are HLA-B22, -B13, -B15, and DR13, respectively. Family studies detected two rare haplotypes: A*11, B*9512, DRB1*14 and A*24, B*52, Cw*07, DRB1*1457, DRB3*020201, DQB1*050301. The gene frequencies of these alleles in the Chinese population are less than 0.0001.

Alleles↗

PubMed2005

Signal transduction mediating gene expression of SP1, LHbeta-subunit and GH in response to GnRH or GHRH in the postnatal and fetal porcine anterior pituitary in vitro.

To clarify signal transduction pathways mediating putative gene expression of transcription factor SP1 (selective promoter factor 1 or specificity protein 1) by GnRH or GHRH porcine anterior pituitary monolayer cultures were exposed for various time periods to GnRH, GHRH, activators of adenylate cyclase (AC) or proteinkinase C (PKC), and mRNA levels of SP1, LHbeta-subunit, and GH were determined by multiplex RT-PCR. In many experiments LH and GH release were measured as well for comparison. Another approach was to inactivate AC, PKC, or proteinkinase A (PKA) by specific inhibitors, MDL, GFX, and H89, respectively. Postnatally (4 weeks) SP1 mRNA level was maximally increased by GnRH, GHRH and both by activation of AC or PKC after 2 h of exposure. Two-hour stimulation of SP1 mRNA levels by dbcAMP was totally blocked by H89, while this inhibitor not clearly blocked GHRH stimulated SP1 mRNA levels. Stimulation of LHbeta mRNA by GnRH was suppressed by inactivation of AC or of PKC but not by inactivation of PKA. Inactivation of AC or PKA but not of PKC inhibited GHRH induced GH mRNA. Already at day 50 of fetal life (and likewise day 80) SP1 mRNA levels were stimulated by GHRH or activation of AC, but not by GnRH or activation of PKC. The results are consistent with the notion that SP1 plays an important role 1) in conferring GnRH responsiveness to the LHbeta-subunit gene by mediating the actions of both AC and PKC and 2) in conferring GHRH responsiveness to the GH gene through activation of the AC probably PKA pathway. Furthermore, the data are in line with the view that the GHRH/AC/SP1/GH pathway develops earlier during fetal life than the GnRH/PKC/SP1/LHbeta pathway.

Adenylyl Cyclases↗

PubMed2005

Halobacillus dabanensis sp. nov. and Halobacillus aidingensis sp. nov., isolated from salt lakes in Xinjiang, China.

Two moderately halophilic spore-forming bacteria were isolated from salt lakes in the Xinjiang region of China. The two strains, designated AD-6(T) and D-8(T), were aerobic, Gram-positive, rod-shaped and motile by means of peritrichous flagella. Strains AD-6(T) and D-8(T) grew in the presence of 0.5-20% and 0.5-25% (w/v) NaCl in complex medium, respectively. Their cell-wall peptidoglycan was of the L-Orn-D-Asp type. The major menaquinone found in both strains was menaquinone-7 (MK-7). The fatty acid profile contained a large amount of branched fatty acids; the main fatty acids were anteiso-C(15:0), anteiso-C(17:0), iso-C(15:0) and iso-C(16:0). The DNA G+C content of strains D-8(T) and AD-6(T) was 41.4 and 42.2 mol%, respectively. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strains D-8(T) and AD-6(T) were located in the genus Halobacillus. Levels of 16S rRNA gene sequence similarity between the isolated strains and the type strains of Halobacillus species were in the range 96.2-99.5%. DNA-DNA relatedness values of 17.0-52.2% were found between the two strains and other Halobacillus species. The DNA-DNA relatedness value between D-8(T) and AD-6(T) was 50.6%. On the basis of phenotypic and chemotaxonomic properties, phylogenetic analysis and genomic distinctiveness, strains D-8(T) and AD-6(T) should be placed in the genus Halobacillus as two novel species, for which the names Halobacillus dabanensis sp. nov. (type strain=JCM 12772(T)=CGMCC 1.3704(T)) and Halobacillus aidingensis sp. nov. (type strain=JCM 12771(T)=CGMCC 1.3703(T)) are proposed, respectively.

Bacillaceae↗

PubMed2003

Cross-section measurement of charged-pion photoproduction from hydrogen and deuterium.

We have measured the differential cross section for the gamman-->pi(-)p and gammap-->pi(+)n reactions at theta(c.m.)=90 degrees in the photon energy range from 1.1 to 5.5 GeV at Jefferson Lab (JLab). The data at E(gamma) greater, similar 3.3 GeV exhibit a global scaling behavior for both pi(-) and pi(+) photoproduction, consistent with the constituent counting rule and the existing pi(+) photoproduction data. Possible oscillations around the scaling value are suggested by these new data. The data show enhancement in the scaled cross section at a center-of-mass energy near 2.2 GeV. The cross section ratio of exclusive pi(-) to pi(+) photoproduction at high energy is consistent with the prediction based on one-hard-gluon-exchange diagrams.

Journal Article↗

PubMed2002

Spine needle biopsy simulator using visual and force feedback.

OBJECTIVE: Biopsy with an inserted needle is an important procedure for lesion detection in the spine, but is difficult to perform due to the presence of many critical organs near the spine. This article presents a spine needle biopsy simulator, based on visual and force feedback, which can be used to plan the optimal path of a needle and to practice the procedure without risk. MATERIALS AND METHODS: The simulator is composed of a 3D human model, a visual-feedback component, a force-feedback component, and an evaluation module. The human model is based on 3D CT data. The visual-feedback component provides an oblique section, multiplanar reformatting images, and a volume-rendered image. Of these, the oblique section display is very useful for planning a 3D path for the needle. During simulation, the force-feedback component generates and provides realistic forces acting on the biopsy needle in real time by synchronizing them to visual feedback. After each simulation, the evaluation module provides a performance analysis for the trainee. RESULTS: For an XCT abdomen volume data set of 256 x 256 x 256, the update rate of image rendering due to needle movement is over 25 Hz, with a force-feedback rate of 1 kHz. This performance proved to be good enough for the trainee to learn the relationship between visual and force feedback. CONCLUSIONS: The simulator is useful for the planning of and training in complicated 3D spine needle biopsy procedures. It may be used as an educational tool for beginners, a practice tool to increase expertise, or a test bed for new procedures.

Algorithms↗

PubMed2002

Investigating the distribution of prostate cancer using three-dimensional computer simulation.

The objective of this work was to investigate the distribution of prostate cancer using three-dimensional (3-D) computer simulation. Two hundred and eighty-one 3-D computer prostate models were constructed from radical prostatectomy specimens. An algorithm was developed which divided each model into 24 symmetrical regions, and it then detected the presence of tumor within an individual region. The distribution rate of prostate cancer was assessed within each region of all 281 prostate models, and the difference between the rates was statistically analyzed using Mantel-Haenszel methodology. There was a statistically significant higher distribution rate of cancer in the posterior half (57.2%) compared to the anterior half ( 40.5%; P=0.001). The base regions (36.8%) had a statistically significant lower distribution rate than either the mid regions (56.3%; P=0.001) or the apical regions (53.5%; P=0.001). The mid regions did have a statistically significant higher distribution rate compared to the apical regions (P=0.032). There was no statistically significant difference between the distribution rate on the left half (48.5%) compared to that on the right half (49.2%; P=0.494). The spatial distribution of prostate cancer can be analyzed using 3-D computer prostate models. The results illustrate that prostate cancer is least commonly located in the anterior half and base regions of the prostate. Through an analysis of the spatial distribution of prostate cancer, we believe that new optimal biopsy strategies and techniques can be developed.

Biopsy↗

PubMed2001

Detailed-term-accounting-approximation calculations of the radiative opacity of laser-produced Al plasmas.

An extensive configuration interaction (CI) scheme and the R-matrix method are combined to calculate the radiative opacity for laser-produced aluminum plasma in local thermodynamic equilibrium using the detailed-term-accounting (DTA) approximation. The CI scheme is used to obtain the absorption oscillator strengths of the electric dipole allowed transitions for evaluating the bound-bound absorption cross sections, and the R-matrix method is used to obtain the bound-free absorption (photoionization) cross sections. For an aluminum plasma at a temperature of 20 eV and the density of 0.01 g/cm(3), the Rosseland and Planck mean opacities are calculated to be 4184 and 24891 cm(2)/g, respectively, by integrating the spectrally resolved opacities with Rosseland and Planck weighting functions. The two mean opacities are also obtained by using the average atom model, and they are 22520 and 30402 cm(2)/g, respectively. The optical transmission from the photon energy of 70-250 eV, which was experimentally measured by Winhart et al. [G. Winhart et al. Phys. Rev. E 53, R1332 (1996)], is also calculated. Generally good agreement is found between our DTA and experimental transmission. Our theoretical result reproduces all structures shown in the experiment, whereas some of the structures near the higher energy edge did not show up in some other opacity models. These structures are attributed to the detailed treatment of the photoionization process.

Journal Article↗

PubMed2001

Azepanone-based inhibitors of human and rat cathepsin K.

The synthesis, in vitro activities, and pharmacokinetics of a series of azepanone-based inhibitors of the cysteine protease cathepsin K (EC 3.4.22.38) are described. These compounds show improved configurational stability of the C-4 diastereomeric center relative to the previously published five- and six-membered ring ketone-based inhibitor series. Studies in this series have led to the identification of 20, a potent, selective inhibitor of human cathepsin K (K(i) = 0.16 nM) as well as 24, a potent inhibitor of both human (K(i) = 0.0048 nM) and rat (K(i,app) = 4.8 nM) cathepsin K. Small-molecule X-ray crystallographic analysis of 20 established the C-4 S stereochemistry as being critical for potent inhibition and that unbound 20 adopted the expected equatorial conformation for the C-4 substituent. Molecular modeling studies predicted the higher energy axial orientation at C-4 of 20 when bound within the active site of cathepsin K, a feature subsequently confirmed by X-ray crystallography. Pharmacokinetic studies in the rat show 20 to be 42% orally bioavailable. Comparison of the transport of the cyclic and acyclic analogues through CaCo-2 cells suggests that oral bioavailability of the acyclic derivatives is limited by a P-glycoprotein-mediated efflux mechanism. It is concluded that the introduction of a conformational constraint has served the dual purpose of increasing inhibitor potency by locking in a bioactive conformation as well as locking out available conformations which may serve as substrates for enzyme systems that limit oral bioavailability.

Administration, Oral↗

PubMed2001

[Expression and clinopathological significance of HCCA1 in hepatocellular carcinoma].

OBJECTIVE: To explore the correlation of a newly cloned HCCA1 gene expression with hepatocellular carcinoma (HCC). METHODS: HCCA1 mRNA and protein expression were detected by Northern blotting and by immunohistochemistry respectively. Its clinopathological significance was also analyzed. RESULTS: HCCA1 mRNA expression was found in 59 (90.8%) out of 65 patients. Of these, 54 (91.5%) showed significantly elevated expression of HCCA1 mRNA in HCC tissues. There were 9 (13.8%) patients who had low level of HCCA1 mRNA expression in paracarcinoma, and 56 (86.2%) cases showed no detectable signals. HCCA1 mRNA expression was closely related to lower tumor grading and portal vein invasion. It was noted that HCCA1 mRNA levels were higher in tumor grading III-IV group than in grading I-II group, higher in portal vein thrombus group than in non-thrombus group. Immunohistochemical staining confirmed that the HCCA1 protein was preferentially expressed in HCC tissues. Amongst 38 patients examined, 20 (52.6%) revealed positive staining with anti-HCCA1. CONCLUSION: HCCA1 is a novel HCC associated gene which may play a role in HCC invasion and metastasis.

Adult↗

PubMed2001

Cyclic ketone inhibitors of the cysteine protease cathepsin K.

Cathepsin K (EC 3.4.22.38), a cysteine protease of the papain superfamily, is predominantly expressed in osteoclasts and has been postulated as a target for the treatment of osteoporosis. Crystallographic and structure--activity studies on a series of acyclic ketone-based inhibitors of cathepsin K have led to the design and identification of two series of cyclic ketone inhibitors. The mode of binding for four of these cyclic and acyclic inhibitors to cathepsin K is discussed and compared. All of the structures are consistent with addition of the active site thiol to the ketone of the inhibitors with the formation of a hemithioketal. Cocrystallization of the C-3 diastereomeric 3-amidotetrahydrofuran-4-one analogue 16 with cathepsin K showed the inhibitor to occupy the unprimed side of the active site with the 3S diastereomer preferred. This C-3 stereochemical preference is in contrast to the X-ray cocrystal structures of the 3-amidopyrrolidin-4-one inhibitors 29 and 33 which show these inhibitors to prefer binding of the 3R diastereomer. The 3-amidopyrrolidin-4-one inhibitors were bound in the active site of the enzyme in two alternate directions. Epimerization issues associated with the labile alpha-amino ketone diastereomeric center contained within these inhibitor classes has proven to limit their utility despite promising pharmacokinetics displayed in both series of compounds.

Animals↗

PubMed2001

Digitized mammography: a clinical trial of postmenopausal women randomly assigned to receive raloxifene, estrogen, or placebo.

BACKGROUND: High mammographic density is associated with increased breast cancer risk. Previous studies have shown that estrogens increase breast density on mammograms, but the effect on mammographic density of selective estrogen receptor modulators, such as raloxifene, is unknown. We assessed changes in mammographic density among women receiving placebo, raloxifene, or conjugated equine estrogens in an osteoporosis prevention trial. METHODS: In a 5-year multicenter, double-blind, randomized, placebo-controlled osteoporosis prevention trial, healthy postmenopausal women who had undergone hysterectomy less than 15 years before the study and had no history of breast cancer received placebo, raloxifene (at one of two doses), or conjugated estrogens (ERT). Women from English-speaking investigative sites who had baseline and 2-year craniocaudal mammograms with comparable positioning (n = 168) were eligible for this analysis. Changes in mammographic density were determined by digital scanning and computer-assisted segmentation of mammograms and were analyzed with the use of analysis of variance. All statistical tests were two-sided. RESULTS: Among the four treatment groups after 2 years on study, the mean breast density (craniocaudal view) was statistically significantly greater in the ERT group than it was in the other three groups (P<0.01 for all three comparisons). Within treatment groups, the mean breast density from baseline to 2 years decreased statistically significantly in women receiving the placebo or either the higher or lower raloxifene dose (P = 0.003, P = 0.002, and P<0.001, respectively) and showed a nonstatistically significant increase in women receiving ERT. CONCLUSIONS: In an osteoporosis prevention trial, raloxifene did not increase breast density after 2 years of treatment. Raloxifene administration should not interfere with, and could even enhance, mammographic detection of new breast cancers.

Breast↗

PubMed2001

Prostate biopsy protocols: 3D visualization-based evaluation and clinical correlation.

OBJECTIVES: Systematic needle core biopsy is commonly used for the diagnosis of prostate cancer by urologists worldwide. As accurate and early diagnosis will result in more and better options for treatment, it is critical that the best possible protocols for biopsy be used clinically. In this study, we develop three-dimensional (3D) modeling and simulation technologies to evaluate most of the biopsy protocols in current clinical use, and correlate the results with those from clinical cases. MATERIALS AND METHODS: Using deformable modeling techniques, 3D computerized prostate surface models were reconstructed from step-sectioned, whole-mounted radical prostatectomy specimens with localized prostate cancer. A 3D computer simulation system was developed to accurately depict the anatomy of the prostate and all individual tumor foci. A user-friendly interface was developed in the system so that a physician can easily and interactively use it for prostate needle core biopsy. A total of 281 prostate models were reconstructed, and 18 biopsies were performed by a urologist on each model to determine the detection rates of seven different biopsy protocols. Clinical biopsies from 35 patient cases were also reviewed and correlated with the simulation results. RESULTS: The most commonly used sextant biopsy had only a 71.5% detection rate, while rates for the 10-pattern and 12-pattern protocols were much higher (96.4% and 97.2%, respectively). Even the lateral 4-pattern protocol performed better than the sextant protocol, with a detection rate of 89.3%. The lateral sextant biopsy protocol (using sites similar to, but more lateral than, those in the sextant protocol) achieved a rate of 92.5%. Although the rate of the 14-pattern biopsy was a little higher (97.5%), it used four more biopsies to achieve this increase, which, according to McNemar's test, is not statistically significant when compared to results with the 10-pattern protocol. The 5-region protocol, which uses 12 biopsies, had a detection rate of 89.7%. Transition zone and seminal vesicle biopsies did not result in a significantly increased detection rate when added to the patterns above. The clinical correlation also confirmed that the 10-pattern protocol was significantly superior to the traditional sextant biopsy pattern. CONCLUSIONS: The 10-pattern biopsy protocol was the most optimized among all the protocols evaluated. This protocol supplemented the sextant biopsy protocol with four more lateral biopsies in the mid and apical sites on both sides.

Biopsy, Needle↗

PubMed2001

Analysis of the factors influencing the therapeutic effects of onychomycosis.

In order to improve the curative effect of onychomycosis, the factors influencing the therapeutic effects were investigated. 545 cases including 245 males and 300 females, who were diagnosed both clinically and mycologically, were treated by Intraconazole with intermittent pulse therapy. The therapeutic effects were judged by the following observations regularly and analyzed from the factors as follows: age; growing speed of nails; accompanied diseases; family history; trauma of nails; infection ways of the pathogens; manifestation of the injury; pathogens; duration of the treatment. The results showed that the recovery rate was higher in younger patients (P < 0.01) with a quicker recovery rate (P < 0.001), and a lower recurrent rate (P < 0.01), as well as in those with quicker growing speed of new-born nail. Also the patients with WSO and DLSO manifestation had a higher recovery rate. The patients with onychomycosis caused by T. rubrum had a higher recovery rate (P < 0.01 to 0.001) no matter whether to prolong the treatment duration. The patients with diabetes mellitus or hyperhidrosis, as well as with positive family history or basic nail diseases such as trauma and paronychia, had a lower recovery rate and the curative effects were not satisfactory. It was concluded that although the single and some DLSO-manifestation nail injury could be cured by internal and external treatments with the help of removing the sick nail and the duration of the treatment could be shortened. The treatment duration should be prolonged in order to increase the curative effects and decrease the recurrence under such conditions as following: old patients above 60 years; patients with low-growing-speed new-borne nails; patients with thumb and big toel injury and ingrowing nail; patients with diabetes mellitus, hyperhidrosis or Renauld's phenomenon; patients with nail trauma before or during the treatment; patients with PSO or TDO manifestation; patients with onychomycosis caused by Candida or Aspergillus; patients with abnormal new-borne nails of abnormal color, coarse surface or abnormal thickness.

Adolescent↗

PubMed2001

Conformational analysis of thiopeptides: free energy calculations on the effects of thio-substitutions on the conformational distributions of alanine dipeptides.

When the oxygen atom in a peptide bond is replaced by a sulfur atom, the restriction in the available conformational space and the ability of thioamides to confer resistance to enzymatic degradation renders thioamides as potentially useful building blocks for drug design and protein engineering. The solvation free energy differences between conformers of the same dipeptide can be high. Yet, previous conformational studies, basing on the (phi, psi) conformational energy maps of thio-substituted dipeptides, neglected both explicit water interactions and free energy considerations. In this paper, the (phi, psi) conformational free energy maps are obtained by single umbrella sampling in an explicit water environment for both alanine dipeptide and the corresponding thioamide derivatives. The phi and psi angles for the minima in the relative energy maps calculated with dielectric of 80 are similar to the corresponding phi and psi angles in the relative free energy maps for both Ac-Ala-NHMe (Ac: acetyl; Ala: alanine) and Act-Alat-NHMe (Act: thio-acetyl; Alat: thio-alanine). However, some large differences between the relative energy and relative free energy of major minima indicate that the consideration of free energy is important in determination of the relative occupancy of particular minima. Free energy maps for both Ac-Ala-NHMe and Act-Alat-NHMe show that thio-substitution favors conformations where phi < 0 because of the deeper beta and alphaR minima. The changes in the position and relative stability of minima were explained in terms of the destabilization of the regions near phi = -120, 0 and 120, psi = 60, -60, 180, which correspond to the increased steric hindrance due to the bulkier sulfur atom.

Alanine↗

PubMed2001

Effects of environmental and test conditions on VOC emissions from "wet" coating materials.

In this paper, numerical simulations have been conducted to study the effects of key environmental and test conditions (air velocity, temperature, film thickness, and sample application time) on volatile organic compound (VOC) emissions from a "wet" coating material (wood stain). Simulation results indicate that air velocity and sample application time only significantly affect the emission profiles in the early stage. Film thickness, on the other hand, affects long-term emissions. Temperature can affect both the short-term and long-term emissions.

Air Movements↗

PubMed2001

Design of inhibitors of Ras--Raf interaction using a computational combinatorial algorithm.

Drugs that inhibit important protein-protein interactions are hard to find either by screening or rational design, at least so far. Most drugs on the market that target proteins today are therefore aimed at well-defined binding pockets in proteins. While computer-aided design is widely used to facilitate the drug discovery process for binding pockets, its application to the design of inhibitors that target the protein surface initially seems to be limited because of the increased complexity of the task. Previously, we had started to develop a computational combinatorial design approach based on the well-known 'multiple copy simultaneous search' (MCSS) procedure to tackle this problem. In order to identify sequence patterns of potential inhibitor peptides, a three-step procedure is employed: first, using MCSS, the locations of specific functional groups on the protein surface are identified; second, after constructing the peptide main chain based on the location of favorite locations of N-methylacetamide groups, functional groups corresponding to amino acid side chains are selected and connected to the main chain C(alpha) atoms; finally, the peptides generated in the second step are aligned and probabilities of amino acids at each position are calculated from the alignment scheme. Sequence patterns of potential inhibitors are determined based on the propensities of amino acids at each C(alpha) position. Here we report the optimization of inhibitor peptides using the sequence patterns determined by our method. Several short peptides derived from our prediction inhibit the Ras--Raf association in vitro in ELISA competition assays, radioassays and biosensor-based assays, demonstrating the feasibility of our approach. Consequently, our method provides an important step towards the development of novel anti-Ras agents and the structure-based design of inhibitors of protein--protein interactions.

Algorithms↗

PubMed2001

[GC-MS analysis of supercritical carbon dioxide extract from seeds of Zanthoxylum bungeanun Maxim].

The chemical components of supercritical carbon dioxide extracts from seeds of Zanthoxylum bungeanun Maxim. were studied by GC-MS-DS. Thirty-five compounds which account for 96.22% of the total area of the chromatographic peaks, were identified. The results showed that fatty acids and esters occupied 90.83% of total chromatographic efflux of the extracts. The main components of the extracts are oleic acid(38.91%), palmitic acid (29.45%), linoleic acid methyl ester(10.80%), linolenic acid methyl ester(8.64%), et al.

Carbon Dioxide↗