Allele frequencies of 18 STR loci in Chinese population.
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China↗
Biomedical subjects
R Li
Publications and source records attributed to R Li.
Localization and physical property experiments conducted by Opportunity at Meridiani Planum.
The location of the Opportunity landing site was determined to better than 10-m absolute accuracy from analyses of radio tracking data. We determined Rover locations during traverses with an error as small as several centimeters using engineering telemetry and overlapping images. Topographic profiles generated from rover data show that the plains are very smooth from meter- to centimeter-length scales, consistent with analyses of orbital observations. Solar cell output decreased because of the deposition of airborne dust on the panels. The lack of dust-covered surfaces on Meridiani Planum indicates that high velocity winds must remove this material on a continuing basis. The low mechanical strength of the evaporitic rocks as determined from grinding experiments, and the abundance of coarse-grained surface particles argue for differential erosion of Meridiani Planum.
Extraterrestrial Environment↗
Soils of Eagle crater and Meridiani Planum at the Opportunity Rover landing site.
The soils at the Opportunity site are fine-grained basaltic sands mixed with dust and sulfate-rich outcrop debris. Hematite is concentrated in spherules eroded from the strata. Ongoing saltation exhumes the spherules and their fragments, concentrating them at the surface. Spherules emerge from soils coated, perhaps from subsurface cementation, by salts. Two types of vesicular clasts may represent basaltic sand sources. Eolian ripples, armored by well-sorted hematite-rich grains, pervade Meridiani Planum. The thickness of the soil on the plain is estimated to be about a meter. The flatness and thin cover suggest that the plain may represent the original sedimentary surface.
Extraterrestrial Environment↗
Pancam multispectral imaging results from the Opportunity Rover at Meridiani Planum.
Panoramic Camera (Pancam) images from Meridiani Planum reveal a low-albedo, generally flat, and relatively rock-free surface. Within and around impact craters and fractures, laminated outcrop rocks with higher albedo are observed. Fine-grained materials include dark sand, bright ferric iron-rich dust, angular rock clasts, and millimeter-size spheroidal granules that are eroding out of the laminated rocks. Spectra of sand, clasts, and one dark plains rock are consistent with mafic silicates such as pyroxene and olivine. Spectra of both the spherules and the laminated outcrop materials indicate the presence of crystalline ferric oxides or oxyhydroxides. Atmospheric observations show a steady decline in dust opacity during the mission. Astronomical observations captured solar transits by Phobos and Deimos and time-lapse observations of sunsets.
Atmosphere↗
The Opportunity Rover's Athena science investigation at Meridiani Planum, Mars.
The Mars Exploration Rover Opportunity has investigated the landing site in Eagle crater and the nearby plains within Meridiani Planum. The soils consist of fine-grained basaltic sand and a surface lag of hematite-rich spherules, spherule fragments, and other granules. Wind ripples are common. Underlying the thin soil layer, and exposed within small impact craters and troughs, are flat-lying sedimentary rocks. These rocks are finely laminated, are rich in sulfur, and contain abundant sulfate salts. Small-scale cross-lamination in some locations provides evidence for deposition in flowing liquid water. We interpret the rocks to be a mixture of chemical and siliciclastic sediments formed by episodic inundation by shallow surface water, followed by evaporation, exposure, and desiccation. Hematite-rich spherules are embedded in the rock and eroding from them. We interpret these spherules to be concretions formed by postdepositional diagenesis, again involving liquid water.
Atmosphere↗
Bacillus cereus pneumonia in a patient with acute lymphoblastic leukemia.
Reported here is a case of Bacillus cereus pneumonia that occurred in a patient with acute lymphoblastic leukemia. The presentation was severe, essentially marked by respiratory distress and pleuritic chest pain. Classic empirical treatment initiated for febrile neutropenia did not cover this rare pathogen and appropriate therapy was therefore delayed. B. cereus is most often a culture contaminant, but it can also be responsible for self-limited gastrointestinal intoxication and, more rarely, severe systemic diseases. Virulence in the case of systemic disease is attributed to tissue necrosis mediated by toxin release. B. cereus pneumonia, as described in the English-language literature, mainly affects immunocompromised patients and most often has a fatal outcome. Thus, the identification of B. cereus in clinical specimens of severely ill immunocompromised patients should lead physicians to question its clinical significance.
Adult↗
Surficial deposits at Gusev Crater along Spirit Rover traverses.
The Mars Exploration Rover Spirit has traversed a fairly flat, rock-strewn terrain whose surface is shaped primarily by impact events, although some of the landscape has been altered by eolian processes. Impacts ejected basaltic rocks that probably were part of locally formed lava flows from at least 10 meters depth. Some rocks have been textured and/or partially buried by windblown sediments less than 2 millimeters in diameter that concentrate within shallow, partially filled, circular impact depressions referred to as hollows. The terrain traversed during the 90-sol (martian solar day) nominal mission shows no evidence for an ancient lake in Gusev crater.
Extraterrestrial Environment↗
Localization and physical properties experiments conducted by Spirit at Gusev Crater.
The precise location and relative elevation of Spirit during its traverses from the Columbia Memorial station to Bonneville crater were determined with bundle-adjusted retrievals from rover wheel turns, suspension and tilt angles, and overlapping images. Physical properties experiments show a decrease of 0.2% per Mars solar day in solar cell output resulting from deposition of airborne dust, cohesive soil-like deposits in plains and hollows, bright and dark rock coatings, and relatively weak volcanic rocks of basaltic composition. Volcanic, impact, aeolian, and water-related processes produced the encountered landforms and materials.
Extraterrestrial Environment↗
Pancam multispectral imaging results from the Spirit Rover at Gusev Crater.
Panoramic Camera images at Gusev crater reveal a rock-strewn surface interspersed with high- to moderate-albedo fine-grained deposits occurring in part as drifts or in small circular swales or hollows. Optically thick coatings of fine-grained ferric iron-rich dust dominate most bright soil and rock surfaces. Spectra of some darker rock surfaces and rock regions exposed by brushing or grinding show near-infrared spectral signatures consistent with the presence of mafic silicates such as pyroxene or olivine. Atmospheric observations show a steady decline in dust opacity during the mission, and astronomical observations captured solar transits by the martian moons, Phobos and Deimos, as well as a view of Earth from the martian surface.
Atmosphere↗
The Spirit Rover's Athena science investigation at Gusev Crater, Mars.
The Mars Exploration Rover Spirit and its Athena science payload have been used to investigate a landing site in Gusev crater. Gusev is hypothesized to be the site of a former lake, but no clear evidence for lacustrine sedimentation has been found to date. Instead, the dominant lithology is basalt, and the dominant geologic processes are impact events and eolian transport. Many rocks exhibit coatings and other characteristics that may be evidence for minor aqueous alteration. Any lacustrine sediments that may exist at this location within Gusev apparently have been buried by lavas that have undergone subsequent impact disruption.
Atmosphere↗
Ki-67 staining is a strong predictor of distant metastasis and mortality for men with prostate cancer treated with radiotherapy plus androgen deprivation: Radiation Therapy Oncology Group Trial 92-02.
PURPOSE: The Ki-67 staining index (Ki67-SI) has been associated with prostate cancer patient outcome; however, few studies have involved radiotherapy (RT) -treated patients. The association of Ki67-SI to local failure (LF), biochemical failure (BF), distant metastasis (DM), cause-specific death (CSD) and overall death (OD) was determined in men randomly assigned to short term androgen deprivation (STAD) + RT or long-term androgen deprivation (LTAD) + RT. PATIENTS AND METHODS: There were 537 patients (35.5%) on Radiation Therapy Oncology Group (RTOG) 92-02 who had sufficient tissue for Ki67-SI analysis. Median follow-up was 96.3 months. Ki67-SI cut points of 3.5% and 7.1% were previously found to be related to patient outcome and were examined here in a Cox proportional hazards multivariate analysis (MVA). Ki67-SI was also tested as a continuous variable. Covariates were dichotomized in accordance with stratification and randomization criteria. RESULTS: Median Ki67-SI was 6.5% (range, 0% to 58.2%). There was no difference in the distribution of patients in the Ki-67 analysis cohort (n = 537) and the other patients in RTOG 92-02 (n = 977) by any of the covariates or end points tested. In MVAs, Ki67-SI (continuous) was associated with LF (P =.08), BF (P =.0445), DM (P <.0001), CSD (P <.0001), and OD (P =.0094). When categoric variables were used in MVAs, the 3.5% Ki67-SI cut point was not significant. The 7.1% cut point was related to BF (P =.09), DM (P =.0008), and CSD (P =.017). Ki67-SI was the most significant correlate of DM and CSD. A detailed analysis of the hazard rates for DM in all possible covariate combinations revealed subgroups of patients treated with STAD + RT that did not require LTAD. CONCLUSION: Ki67-SI was the most significant determinant of DM and CSD and was also associated with OD. The Ki67-SI should be considered for the stratification of patients in future trials.
Adult↗
Structural basis for integrin alphaIIbbeta3 clustering.
We have expressed two proteins that correspond to the transmembrane and cytoplasmic domains of integrin alphaIIb and beta3 subunits. Characterization of these proteins, dispersed in anionic and zwitterionic micelles, revealed that, rather than interacting with each other, the two proteins associated into homodimers and homotrimers respectively. Moreover, studies using the TOXCAT assay system confirmed that the alphaIIb and beta3 transmembrane domains can self-associate in biological cell membranes. Transmembrane domain-mediated homo-oligomerization provides a plausible structural basis for integrin clustering and could promote integrin activation as well. Indeed, replacing specific residues in the transmembrane helix of either alphaIIb or beta3 with an asparagine residue resulted in a facilitated homo-oligomerization of the mutated transmembrane helix, promoted the formation of integrin clusters on the cell surface and shifted alphaIIbbeta3 to its activated state. Thus these studies support the hypothesis that the transmembrane domains play a vital role in the function and regulation of alphaIIbbeta3.
Amino Acid Motifs↗
Pharmacokinetics and disposition of clenbuterol in the horse.
The pharmacokinetics of clenbuterol (CLB) following a single intravenous (i.v.) and oral (p.o.) administration twice daily for 7 days were investigated in thoroughbred horses. The plasma concentrations of CLB following i.v. administration declined mono-exponentially with a median elimination half-life (t(1/2k)) of 9.2 h, area under the time-concentration curve (AUC) of 12.4 ng.h/mL, and a zero-time concentration of 1.04 ng/mL. Volume of distribution (V(d)) was 1616.0 mL/kg and plasma clearance (Cl) was 120.0 mL/h/kg. The terminal portion of the plasma curve following multiple p.o. administrations also declined mono-exponentially with a median elimination half-life (t(1/2k)) of 12.9 h, a Cl of 94.0 mL/h/kg and V(d) of 1574.7 mL/kg. Following the last p.o. administration the baseline plasma concentration was 537.5 +/- 268.4 and increased to 1302.6 +/- 925.0 pg/mL at 0.25 h, and declined to 18.9 +/- 7.4 pg/mL at 96 h. CLB was still quantifiable in urine at 288 h following the last administration (210.0 +/- 110 pg/mL). The difference between plasma and urinary concentrations of CLB was 100-fold irrespective of the route of administration. This 100-fold urine/plasma difference should be considered when the presence of CLB in urine is reported by equine forensic laboratories.
Administration, Oral↗
Distribution and shifting trends of bacterial keratitis in north China (1989-98).
AIMS: To study the distribution and shifting trends of bacterial keratitis. METHODS: The data of 2220 corneal isolates from 1 January 1989 to 31 December 1998 were reviewed retrospectively. RESULTS: Positive culture was recovered in 490 isolates. Gram positive cocci and Gram negative bacilli represented 51% and 39.4%, respectively. Pseudomonas aeruginosa was the most common pathogen (32.2%). A gradual increase in the percentage of Gram positive cocci coupled with a decrease of Gram negative bacilli. CONCLUSION: Pseudomonas aeruginosa and coaculase negative Staphylococcus were the most common pathogens in bacterial keratitis in north China.
China↗
Molecular analysis of the mitochondrial 12S rRNA and tRNASer(UCN) genes in paediatric subjects with non-syndromic hearing loss.
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Adolescent↗
Direct evidence for recycling of myeloperoxidase-catalyzed phenoxyl radicals of a vitamin E homologue, 2,2,5,7,8-pentamethyl-6-hydroxy chromane, by ascorbate/dihydrolipoate in living HL-60 cells.
Myeloperoxidase (MPO)-catalyzed one-electron oxidation of endogenous phenolic constituents (e.g., antioxidants, hydroxylated metabolites) and exogenous compounds (e.g., drugs, environmental chemicals) generates free radical intermediates: phenoxyl radicals. Reduction of these intermediates by endogenous reductants, i.e. recycling, may enhance their antioxidant potential and/or prevent their potential cytotoxic and genotoxic effects. The goal of this work was to determine whether generation and recycling of MPO-catalyzed phenoxyl radicals of a vitamin E homologue, 2,2,5,7,8-pentamethyl-6-hydroxychromane (PMC), by physiologically relevant intracellular reductants such as ascorbate/lipoate could be demonstrated in intact MPO-rich human leukemia HL-60 cells. A model system was developed to show that MPO/H(2)O(2)-catalyzed PMC phenoxyl radicals (PMC*) could be recycled by ascorbate or ascorbate/dihydrolipoic acid (DHLA) to regenerate the parent compound. Absorbance measurements demonstrated that ascorbate prevents net oxidation of PMC by recycling the phenoxyl radical back to the parent compound. The presence of DHLA in the reaction mixture containing ascorbate extended the recycling reaction through regeneration of ascorbate. DHLA alone was unable to prevent PMC oxidation. These conclusions were confirmed by direct detection of PMC* and ascorbate radicals formed during the time course of the reactions by EPR spectroscopy. Based on results in the model system, PMC* and ascorbate radicals were identified by EPR spectroscopy in ascorbate-loaded HL-60 cells after addition of H(2)O(2) and the inhibitor of catalase, 3-aminotriazole (3-AT). The time course of PMC* and ascorbate radicals was found to follow the same reaction sequence as during their recycling in the model system. Recycling of PMC by ascorbate was also confirmed by HPLC assays in HL-60 cells. Pre-loading of HL-60 cells with lipoic acid regenerated ascorbate and thus increased the efficiency of ascorbate in recycling PMC*. Lipoic acid had no effect on PMC oxidation in the absence of ascorbate. Thus PMC phenoxyl radical does not directly oxidize thiols but can be recycled by dihydrolipoate in the presence of ascorbate. The role of phenoxyl radical recycling in maintaining antioxidant defense and protecting against cytotoxic and genotoxic phenolics is discussed.
Antioxidants↗
Mapping the antigenicity of copper-treated cellular prion protein with the scrapie isoform.
When recombinant and cellular prion protein (PrP(C)) binds copper, it acquires properties resembling the scrapie isoform (PrP(Sc)), namely protease resistance, detergent insolubility and increased beta sheet content. However, whether the conformations of PrP(C) induced by copper and PrP(Sc) are similar has not been studied in great detail. Here, we use a panel of seven monoclonal antibodies to decipher the epitopes on full-length mouse PrP(C) that are affected by exogenous copper, and to compare the antigenicity of the copper-treated full-length PrP(C) with the full-length PrP(Sc) present in scrapie-infected mouse brains. In the presence of copper, we found that epitopes along residues 115-130 and 153-165 become more accessible on PrP(C). These regions correspond to the two beta sheet strands in recombinant PrP and they were proposed to be important for prion conversion. However, when we compared the antibody-binding patterns between full-length PrP(C) with full-length PrP(Sc) and between copper-treated full-length PrP(C) with full-length PrP(Sc), antibody binding to residues 143-155 and 175-185 was consistently increased on PrP(Sc). Collectively, our results suggest that copper-treated full-length PrP(C) does not resemble full-length PrP(Sc), despite acquiring PrP(Sc)-like properties. In addition, since each full-length protein reacts distinctively to some of the antibodies, this binding pattern could discriminate between PrP(C) and PrP(Sc).
Animals↗
A multicenter phase II study of the efficacy and safety of docetaxel plus cisplatin in Asian chemonaïve patients with metastatic or locally advanced non-small cell lung cancer.
AIMS: To evaluate the efficacy and safety of docetaxel-cisplatin in patients with metastatic or locally advanced non-small cell lung cancer (NSCLC). METHODS: Chemotherapy-naïve patients with histologically confirmed TNM stage III or IV NSCLC were recruited from 12 Asian trial centers. Patients received docetaxel (75 mg/m2) and cisplatin (75 mg/m2) every 3 weeks for 6 cycles. RESULTS: 130 of 146 patients were evaluable for efficacy (60% stage IV). Three complete and 58 partial responses were observed (overall response rate: 46.9%; 95% CI: 38.3-55.5%). Median time to progression was 6.9 months and median survival was 14.0 months; 1-year survival was 59.5%. Grade 3/4 neutropenia, thrombocytopenia and anemia occurred in 69.2%, 6.2% and 18.5% of patients, respectively. Grade 3/4 vomiting was observed in 13.7% and grade 3/4 neurosensory effects were observed in 2.7% of patients. There was one case of treatment-related death due to sepsis. CONCLUSION: Docetaxel-cisplatin is an effective and well-tolerated treatment in Asian patients with NSCLC.
Adult↗