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Biomedical subjects

J He

Publications and source records attributed to J He.

At least 19 recordsLinked to original sources
PubMed2007

Timing of drotrecogin alfa (activated) initiation in treatment of severe sepsis: a database cohort study of hospital mortality, length of stay, and costs.

INTRODUCTION: For patients with critical conditions including severe sepsis, minimizing the time from presentation to treatment is important to improving outcomes. Understanding the factors influencing high hospital mortality and resource utilization in severe sepsis continues to interest clinicians and researchers. This study examined the associations between timing of drotrecogin alfa (activated) (DrotAA) initiation and hospital mortality, length-of-stay, and costs. METHODS: We conducted a cohort study of adult patients (N = 1179) with intensive care unit stays from November 2001 to June 2003 who received DrotAA in US hospitals with data in the Solucient ACTracker database. We defined evident severe sepsis (ESS) as concurrent antibiotic plus ventilator and/or vasopressor use. We characterized the interval between ESS and DrotAA initiation as Same-day, Next-day, or Day 2+. We compared group characteristics and created multivariate models of hospital mortality, length-of-stay, and costs. RESULTS: Forty-three percent of patients received Same-day DrotAA, 30% Next-day, and 27% Day 2+. Same-day and Next-day patients had more organ dysfunctions at ICU admission than Day 2+ patients (1.1 +/- 0.9 and 1.2 +/- 0.8 vs. 1.0 +/- 0.8; p = 0.021 and p < 0.001, respectively), but from ESS to DrotAA initiation, organ dysfunctions for Day 2+ patients had increased more (+0.0 and +0.4 vs. +0.6, respectively; all p < 0.0001). Increased mortality was observed with administration later than Same-day, although only for the Day 2+ group did the association remain significant (p < 0.05) after adjusting for clinical and demographic factors. Only Next-day initiation was associated with significantly decreased costs (p = 0.0145). CONCLUSIONS: Timing of DrotAA initiation is associated with clinical and economic outcomes in severe sepsis. The potential impact of this timing on hospital mortality, length-of-stay, and costs deserves further study.

Adolescent↗
PubMed2006

Sensitive and selective liquid chromatography-mass spectrometry method for the quantification of rosiglitazone in human plasma.

A sensitive and selective high-performance liquid chromatography-electrospray ionisation-tandem mass spectrometry (HPLC-ESI-MS-MS) method for determination of rosiglitazone in human plasma has been developed. After the addition of the internal standard, plasma samples were precipitated by acetonitrile. The compounds were separated on a proC18 column using a mixture of ammonium acetate buffer (0.02 M, pH 6.5) and acetonitrile (in the ratio of 47:53, v/v) as mobile phase. A Finnigan LCQdeca plus ion trap mass spectrometer connected to a Finnigan Surveyor HPLC was used to develop and validate the method. Linearity was established for the range of concentrations 1-1000 ng/ml with a coefficient of determination (r(2)) of 0.999. The intra-day accuracy for rosiglitazone ranged from 110.0 to 99.2% at low, medium and high levels. The inter-day accuracy was less than 15%. The lower limit of quantitation (LLOQ) was identified reproducible at 1.0 ng/ml with a precision of 5.7%. After validation, the method was used to study the pharmacokinetic profile of rosiglitazone in five healthy volunteers after administration of a single oral dose (4.0mg). The proposed method enabled the unambiguous evaluation and quantitation of rosiglitazone for pharmacokinetic, bioavailability or drug-drug interaction studies. A possible chromatography peak (m/z 121, its parent ion m/z 344) of N-demethyl rosiglitazone was observed at 3.49 min during determining rosiglitazone. This may be also a potential method for simultaneous determination of rosiglitazone and its metabolite N-demethyl rosiglitazone concentrations in plasma.

Administration, Oral↗
PubMed2006

New Luttinger-liquid physics from photoemission on Li0.9M06O17.

Temperature dependent high resolution photoemission spectra of quasi-one-dimensional Li(0.9)Mo(6)O(17)evince a strong renormalization of its Luttinger-liquid density-of-states anomalous exponent. We trace this new effect to interacting charge neutral critical modes that emerge naturally from the two-band nature of the material. Li(0.9)Mo(6)O(17) is shown thereby to be a paradigm material that is capable of revealing new Luttinger physics.

Journal Article↗
PubMed2006

A randomized controlled trial of dietary fiber intake on serum lipids.

OBJECTIVE: Clinical trials have indicated that water-soluble fiber from oats reduces serum cholesterol among hypercholesterolemic patients on a low-fat diet. We examined the effect of dietary fiber intake on serum lipids among persons without hypercholesterolemia. DESIGN: Randomized controlled trial. SETTING AND SUBJECTS: We recruited 110 participants who were aged 30-65 years and had a serum cholesterol level < 240 mg/dl from community. INTERVENTION: Study participants were randomly assigned to receive 8 g per day of water-soluble fiber from oat bran or a control intervention. RESULTS: At baseline, the mean levels of serum cholesterol and other measured variables were comparable between the high-fiber and control groups. Over the 3-month intervention, mean changes (95% confidence interval (CI)) in total, HDL-, and LDL-cholesterol were -2.42 mg/dl (-8.90 to 4.05 mg/dl; P = 0.46), -0.24 mg/dl (-2.19 to 1.71 mg/dl; P = 0.81), and -1.96 mg/dl (-7.32 to 3.40 mg/dl; P = 0.47) in the fiber group and -0.02 mg/dl (-5.29 to 5.26 mg/dl; P = 0.99), 1.42 mg/dl (-0.74 to 3.59 mg/dl; P = 0.19), and -0.64 mg/dl (-5.30 to 4.03 mg/dl; P = 0.79) in the control group, respectively. The net changes (95% confidence interval) in total, HDL-, and LDL-cholesterol were -2.40 mg/dl (-10.6 to 5.81 mg/dl; P = 0.56), -1.66 mg/dl (-4.55 to 1.22 mg/dl; P = 0.26) and -1.33 mg/dl (-8.33 to 5.68 mg/dl; P = 0.71), respectively. CONCLUSIONS: Our study does not support the hypothesis that water-soluble fiber intake from oat bran reduces total and LDL-cholesterol in study participants with a normal serum cholesterol level.

Adult↗
PubMed2006

Molecular detection and sequence analysis of a new hepatitis E virus isolate from Pakistan.

Sporadic and epidemic acute viral hepatitis E in many developing countries is caused by hepatitis E virus (HEV). The HEV genome has been classified into three major genotypes. However, extensive diversity has been noted among HEV isolates from patients with acute hepatitis in China and Taiwan. Some reports indicated that multiple genotypes of HEV could cocirculate in the same area; even distinct genotypes of HEV could exist in the same patient. Pakistan is a highly endemic area for hepatitis E. So far only two Pakistan HEV isolates Sar-55 (87-Pakistan-A) and Abb-2B (88-Pakistan-2B) have been characterized, and the nucleotide sequences of these two HEV isolates show only 90% homology. In this study, a third HEV isolate from Pakistan (87-Pakistan-B) is reported. The sequences of a 438-bp fragment from ORF-2 and a 259-bp fragment from the ORF-1-3 region of this new HEV isolate were obtained and sequenced. The sequence analysis showed that this new HEV isolate was very closely related to the Sar-55 but different from the Abb-2B HEV isolate. These results indicated that the Sar-55 (87-Pakistan-A) genotype is the main endemic HEV strain in the Sargodha area. These data will be useful for HEV epidemiological studies, diagnosis and vaccine development.

Base Sequence↗
PubMed2006

Investigation of killer cell immunoglobulin-like receptor KIR2DL4 diversity by sequence-based typing in Chinese population.

Human killer cell immunoglobulin-like receptors (KIRs) play an important role in controlling natural killer (NK) cell function. Here, polymerase chain reaction sequence-based typing (PCR-SBT) procedures identifying alleles of the KIR2DL4 gene have been established. The method was designed around the specific amplification of exon 3 to exon 5 and exon 7 to exon 9 of the KIR2DL4 gene and produce discrimination of KIR2DL4 alleles. Genomic DNAs from 83 healthy unrelated Chinese Han individuals were typed for KIR2DL4 alleles by this method. Each sample was assigned to the putative KIR2DL4 allele combination according to the nucleotide polymorphism profiles of all KIR2DL4 alleles. Twenty-one different genotypes and seven KIR2DL4 alleles were observed in the population, with KIR2DL4*00102 having the highest frequency, 0.5. Five individuals bear a recombinant allele KIR3DP*004 that associated with three putative KIR2DL4 alleles. Our data demonstrated that the established PCR-SBT method for KIR2DL4 allele typing was reliable, and Chinese Han population is distinct in KIR2DL4 allele frequencies in comparison to some other populations.

Alleles↗
PubMed2006

Controlled synthesis and field emission properties of ZnO nanostructures with different morphologies.

By simply controlling atmosphere, rods, tetraleg-rods, and arrays of ZnO nanostructures have been fabricated respectively through pure zinc powder evaporation without catalyst at temperature of 650 - 700 degrees C. Investigations through HRTEM and XRD showed that the growth of the synthesized ZnO nanostructures was controlled by vapor-solid mechanism. Field emission measurements revealed that all of the structures, owing to their very low turn-on voltage, sufficient emission current and proper linearity of 1/V - Ln(l/V2), are likely to be potential candidates as a field emitter. The results also indicated that field emission properties are relative to morphology and size of the tips of ZnO nanostructures, and the nanorods with sharp tips possess the first-class FE property.

Crystallization↗
PubMed2006

Enhancing urban infrastructure investment planning practices for a changing climate.

Climate change raises many concerns for urban water management because of the effects on all aspects of the hydrological cycle. Urban water infrastructure has traditionally been designed using historical observations and assuming stationary climatic conditions. The capability of this infrastructure, whether for storm-water drainage, or water supply, may be over- or under-designed for future climatic conditions. In particular, changes in the frequency and intensity of extreme rainfall events will have the most acute effect on storm-water drainage systems. Therefore, it is necessary to take future climatic conditions into consideration in engineering designs in order to enhance water infrastructure investment planning practices in a long time horizon. This paper provides the initial results of a study that is examining ways to enhance urban infrastructure investment planning practices against changes in hydrologic regimes for a changing climate. Design storms and intensity-duration-frequency curves that are used in the engineering design of storm-water drainage systems are developed under future climatic conditions by empirically adjusting the general circulation model output, and using the Gumbel distribution and the Chicago method. Simulations are then performed on an existing storm-water drainage system from NE Calgary to investigate the resiliency of the system under climate change.

Alberta↗
PubMed2006

Human platelet alloantigen systems in three Chinese ethnic populations.

Knowledge of the prevalence of human platelet antigens (HPA) in different populations is important for effective diagnosis and management of immune-mediated platelet disorders. The purpose of this study was to determine HPA gene frequencies in the majority Han ethnic population of China and in ethnic She and Tajik minority populations. Using PCR sequence specific primers, HPA- 1, -2, -3, -4, -5, and -6, we determined genotypes for ethnic Han, She, and Tajik blood donors. HPA gene frequencies for Chinese Han were found to be similar to those of She, reflecting the historic affinities of these two populations. HPA gene frequencies for Tajik were closer to those for Caucasians than to Chinese Han, She, or other Asian populations, reflecting their disparate origin and historic geographic isolation. HPA gene frequencies in these Chinese populations reflect their historic origins. Knowledge of these findings may be used to better understand and treat immune-mediated platelet disorders in these populations.

Antigens, Human Platelet↗
PubMed2005

Neurogenesis in adolescent brain is potently inhibited by ethanol.

Adolescence is a period of progressive changes in brain that likely contribute to the maturation of behavior. Human adolescents consume large amounts of ethanol. To investigate the effects of ethanol on adolescent neural progenitor cells, male rats (35-40 days old) were treated with an acute dose of ethanol (1.0, 2.5 or 5.0 g/kg, i.g.) or vehicle that resulted in peak blood levels of 33, 72, and 131 mg/dl, respectively. Bromodeoxyuridine (300 mg/kg i.p.) was administered to label dividing cells and rats were killed at 5 h to assess proliferation or at 28 days to assess cell survival and differentiation. After 5 h, bromodeoxyuridine-immunoreactivity was reduced by 63, 97 and 99% in the rostral migratory stream and 34, 71 and 99% in the subventricular zone by 1.0, 2.5 and 5.0 g/kg of ethanol respectively. In the dentate gyrus, ethanol reduced bromodeoxyuridine-immunoreactivity by 29, 40, and 78% at the three doses respectively. The density of doublecortin immunoreactivity was decreased after 3 days and the number of bromodeoxyuridine+ cells remained decreased at 28 days when most hippocampal bromodeoxyuridine+ cells coexpressed neuronal nuclei, a neuronal marker. These studies indicate that the adolescent brain is very sensitive to acute ethanol inhibition of neurogenesis.

Aging↗
PubMed2005

Dual inhibition of the epidermal growth factor and vascular endothelial growth factor phosphorylation for antivascular therapy of human prostate cancer in the prostate of nude mice.

BACKGROUND: Androgen-independent prostate cancer (PCa) may be susceptible to modulation of the tumor microenvironment. We determined whether a dual tyrosine kinase inhibitor (AEE788) of the epidermal growth factor receptor (EGF-R) and vascular endothelial growth factor receptor (VEGF-R) combined with chemotherapy can produce therapy of human PCa in nude mice. METHODS: PC-3MM2 human PCa cells were injected into the prostate of nude mice. Three days later, the mice were randomized into four groups: saline control, paclitaxel, AEE788, and AEE788 and paclitaxel. The mice were treated for 5 weeks and necropsied. Tumor incidence, weight, and incidence of lymph node metastasis were recorded. Tumor tissue was analyzed immunohistochemically. RESULTS: Treatment of mice with AEE788 or AEE788 plus paclitaxel significantly decreased tumor incidence, total tumor weight, and incidence of lymph node metastasis. AEE788 treatment alone or in combination with paclitaxel inhibited the phosphorylation of EGF-R and VEGF-R on tumor cells and tumor-associated endothelial cells. Therapeutic efficacy correlated with an increase in apoptosis of tumor cells and tumor-associated endothelial cells. CONCLUSION: Blockade of EGF-R and VEGF-R signaling pathways coupled with chemotherapy suppressed the progressive growth and metastasis of human PCa cells growing orthotopically in nude mice.

Animals↗
PubMed2005

Non-fermi-liquid behavior in quasi-one-dimensional Li0.9Mo6O17.

We present temperature dependent scanning tunneling spectroscopy data of the quasi-one-dimensional conductor Li0.9Mo6O17. The differential tunneling current in our low-temperature spectra shows a power-law behavior around the Fermi energy, which is expected for a clean Luttinger liquid. The power-law exponent is found to be 0.6. Spectra for a temperature range of 5 to 55 K can be fitted fairly well with a model for tunneling into a Luttinger liquid at the appropriate temperature. A fit with a model based on a zero bias anomaly is significantly worse compared to the Luttinger liquid model. No signature of a phase transition at T = 24 K is observed in our temperature dependent data.

Journal Article↗
PubMed2005

Goldstone-mode phonon dynamics in the pyrochlore Cd2Re2O7.

We have measured the polarized Raman scattering spectra of Cd2Re2O7, the first superconducting pyrochlore, as a function of temperature. For temperatures below the cubic-to-tetragonal structural phase transition (SPT) at 200 K, a peak with B1 symmetry develops at zero frequency with divergent intensity. We identify this peak as the first observation of the Goldstone phonon in a crystalline solid. The Goldstone phonon is a collective excitation that exists due to the breaking of the continuous symmetry with the SPT. Its emergence coincides with that of a Raman-active soft mode. The order parameter for both features derives from an unstable doubly degenerate vibration (with Eu symmetry) of the O1 atoms which drives the SPT.

Journal Article↗
PubMed2005

Development and evaluation of biocompatible films of polytetrafluoroethylene polymers holding lithium phthalocyanine crystals for their use in EPR oximetry.

Electron paramagnetic resonance (EPR) oximetry is a powerful technology that allows the monitoring of oxygenation in tissues. The measurement of tissue oxygenation can be achieved using lithium phthalocyanine (LiPc) crystals as oxygen reporters. In order to have biocompatibility for the sensing system and to assure long-term stability in the responsiveness of the system, we developed films of Teflon AF 2400 with embedded LiPc crystals. These systems can be used as retrievable inserts or parts of an implantable resonator or catheter. Atomic force microscopy studies revealed that the surface of the films was regular and planar. The response to oxygen of the sensor (EPR linewidth as a function of pO(2)) remained unchanged after implantation in mice, and was not affected by sterilization or irradiation. The use of resonators, holding LiPc embedded in Teflon AF 2400, implanted in the gastrocnemius muscle of rabbits allowed the monitoring of oxygen during several weeks. Several assays also demonstrated the biocompatibility of the system: (1) no hemolytic effect was noted; (2) no toxicity was found using the systemic injection test of extracts; (3) histological analysis in rabbit muscle in which the films were implanted for 1 week or 3 months was similar to standard polyethylene biocompatible devices. These advanced oxygen sensors are promising tools for future pre-clinical and clinical developments of EPR oximetry. These developments can be applied for other applications of biosensors where there is a need for oxygen permeable membranes.

Absorption↗