Biomedical subjects

Yue Zhou

Publications and source records attributed to Yue Zhou.

At least 37 records · Page 2Linked to original sources

PubMed2005

Characterization of marine aerosol for assessment of human exposure to brevetoxins.

Red tides in the Gulf of Mexico are commonly formed by the fish-killing dinoflagellate Karenia brevis, which produces nine potent polyether brevetoxins (PbTxs). Brevetoxins can be transferred from water to air in wind-powered white-capped waves. Inhalation exposure to marine aerosol containing brevetoxins causes respiratory symptoms. We describe detailed characterization of aerosols during an epidemiologic study of occupational exposure to Florida red tide aerosol in terms of its concentration, toxin profile, and particle size distribution. This information is essential in understanding its source, assessing exposure to people, and estimating dose of inhaled aerosols. Environmental sampling confirmed the presence of brevetoxins in water and air during a red tide exposure period (September 2001) and lack of significant toxin levels in the water and air during an unexposed period (May 2002). Water samples collected during a red tide bloom in 2001 showed moderate-to-high concentrations of K. brevis cells and PbTxs. The daily mean PbTx concentration in water samples ranged from 8 to 28 microg/L from 7 to 11 September 2001; the daily mean PbTx concentration in air samples ranged from 1.3 to 27 ng/m(3). The daily aerosol concentration on the beach can be related to PbTx concentration in water, wind speed, and wind direction. Personal samples confirmed human exposure to red tide aerosols. The particle size distribution showed a mean aerodynamic diameter in the size range of 6-12 microm, with deposits mainly in the upper airways. The deposition pattern correlated with the observed increase of upper airway symptoms in healthy lifeguards during the exposure periods.

Aerosols↗

PubMed2005

Initial evaluation of the effects of aerosolized Florida red tide toxins (brevetoxins) in persons with asthma.

Florida red tides annually occur in the Gulf of Mexico, resulting from blooms of the marine dinoflagellate Karenia brevis. K. brevis produces highly potent natural polyether toxins, known as brevetoxins, that activate voltage-sensitive sodium channels. In experimental animals, brevetoxins cause significant bronchoconstriction. A study of persons who visited the beach recreationally found a significant increase in self-reported respiratory symptoms after exposure to aerosolized Florida red tides. Anecdotal reports indicate that persons with underlying respiratory diseases may be particularly susceptible to adverse health effects from these aerosolized toxins. Fifty-nine persons with physician-diagnosed asthma were evaluated for 1 hr before and after going to the beach on days with and without Florida red tide. Study participants were evaluated with a brief symptom questionnaire, nose and throat swabs, and spirometry approved by the National Institute for Occupational Safety and Health. Environmental monitoring, water and air sampling (i.e., K. brevis, brevetoxins, and particulate size distribution), and personal monitoring (for toxins) were performed. Brevetoxin concentrations were measured by liquid chromatography mass spectrometry, high-performance liquid chromatography, and a newly developed brevetoxin enzyme-linked immunosorbent assay. Participants were significantly more likely to report respiratory symptoms after Florida red tide exposure. Participants demonstrated small but statistically significant decreases in forced expiratory volume in 1 sec, forced expiratory flow between 25 and 75%, and peak expiratory flow after exposure, particularly those regularly using asthma medications. Similar evaluation during nonexposure periods did not significantly differ. This is the first study to show objectively measurable adverse health effects from exposure to aerosolized Florida red tide toxins in persons with asthma. Future studies will examine the possible chronic effects of these toxins among persons with asthma and other chronic respiratory impairment.

Adolescent↗

PubMed2005

Occupational exposure to aerosolized brevetoxins during Florida red tide events: effects on a healthy worker population.

Karenia brevis (formerly Gymnodinium breve) is a marine dinoflagellate responsible for red tides that form in the Gulf of Mexico. K. brevis produces brevetoxins, the potent toxins that cause neurotoxic shellfish poisoning. There is also limited information describing human health effects from environmental exposures to brevetoxins. Our objective was to examine the impact of inhaling aerosolized brevetoxins during red tide events on self-reported symptoms and pulmonary function. We recruited a group of 28 healthy lifeguards who are occupationally exposed to red tide toxins during their daily work-related activities. They performed spirometry tests and reported symptoms before and after their 8-hr shifts during a time when there was no red tide (unexposed period) and again when there was a red tide (exposed period). We also examined how mild exercise affected the reported symptoms and spirometry tests during unexposed and exposed periods with a subgroup of the same lifeguards. Environmental sampling (K. brevis cell concentrations in seawater and brevetoxin concentrations in seawater and air) was used to confirm unexposed/exposed status. Compared with unexposed periods, the group of lifeguards reported more upper respiratory symptoms during the exposed periods. We did not observe any impact of exposure to aerosolized brevetoxins, with or without mild exercise, on pulmonary function.

Adolescent↗

PubMed2005

Bimodality of 2-h plasma glucose distributions in whites: the Rancho Bernardo study.

OBJECTIVE: Several studies have shown a bimodal curve in the distribution of glucose in populations with a high prevalence of type 2 diabetes, but bimodality has not been reported among whites of Northern European ancestry. It is not clear whether this difference reflects the lower prevalence of diabetes, obscuring a second mode, or implies a more fundamental difference between whites and nonwhites. We investigate this issue by studying glucose distributions in older white patients. RESEARCH DESIGN AND METHODS: A study of diabetes was conducted among older community-dwelling white residents of a suburban Southern California community between 1984 and 1987. Two-hour plasma glucose data were collected from 2,326 older white men and women aged 23-92. To investigate bimodality of glucose distributions, we fit unimodal and bimodal normal models to 2-h plasma glucose concentrations transformed by the Box-Cox family of transformations. RESULTS: We found that the bimodal normal mixture model fit the data significantly better than the unimodal skewed distribution model for both sexes and all age-groups except those > or =80 years. The cut points separating the two modes were generally within the 11.1- to 13.6-mmol/l range. CONCLUSIONS: The bimodality of glucose distributions among whites, combined with previous findings, indicates that this phenomenon may be universal. A smaller second mode in our study compared with other studies suggests that whites have diabetes susceptibility but may require more obesity to demonstrate it. With increasing obesity in the U.S., the predicted epidemic of diabetes may affect all ethnic groups including whites.

Adult↗

PubMed2005

[Plasticity and application of marrow-derived stem cells].

OBJECTIVE: To investigate plasticity of marrow-derived stem cells, possible mechanisms and application. METHODS: The recent literature concerned plasticity of marrow-derived stem cells was extensively reviewed. RESULTS: Although stem cells plasticity has not been proven, there is more and more evidence to show that the stem cells may have the plasticity and at least four different mechanisms are explained. CONCLUSION: The extensive research will be required. If the plasticity is proven, adult stem cells can be used for more therapeutic purposes. For example, the use of stem cells from bone marrow may correct genetic or degenerative disorders of a second organ from which stem cells are more difficult to isolate.

Animals↗

PubMed2005

[Detection of PVCs with support vector machine].

The classifiction of heart beats is the foundation for automated arrhythmia monitoring devices. Support vector machnies (SVMs) have meant a great advance in solving classification or pattern recognition. This study describes SVM for the identification of premature ventricular contractions (PVCs) in surface ECGs. Features for the classification task are extracted by analyzing the heart rate, morphology and wavelet energy of the heart beats from a single lead. The performance of different SVMs is evaluated on the MIT-BIH arrhythmia database following the association for the advancement of medical instrumentation (AAMI) recommendations.

Artificial Intelligence↗

PubMed2005

Medical nebulizer performance: effects of cascade impactor temperature.

BACKGROUND: During operation of a jet nebulizer, the temperature of the nebulizer outlet could decrease by more than 10 degrees C, depending on the nebulizer type and operating conditions, such as driving flow rate and fill volume. The droplet size distribution generated from the nebulizer can be measured by a cascade impactor. However, when the cascade impactor is operated at ambient room temperature, the droplets could evaporate because of the temperature difference between the nebulizer outlet and the body of the impactor. METHODS: An 8-stage cascade impactor was used to measure the particle size distribution from 4 different types of jet nebulizer (LC Plus, Side-Stream, VixOne, and Micromist) in 2 temperature conditions: ambient (22 degrees C) and low (10 degrees C). Two different formulations, albuterol (aqueous solution) and budesonide (suspension), were used. RESULTS: There was a significantly larger (p < 0.05) mass median aerodynamic diameter and smaller respirable fraction for each nebulizer with the impactor at low temperature than with the impactor at ambient temperature. The mass median aerodynamic diameter of the nebulizers with the impactor operating at low temperature appeared 15-130% larger than with the impactor operating at ambient temperature, for both formulations. The respirable fraction also changed from 10% when the impactor was operated at low temperature to 65% when the impactor was operated at ambient temperature. CONCLUSION: The results provide important information for the use of a cascade impactor to measure the particle-size distribution of nebulizer aerosols.

Administration, Inhalation↗

PubMed2005

[Influence of fluorescent protein expression on the proliferation of NIH3T3 cells in vitro].

OBJECTIVE: To investigate the influence of fluorescent protein expression on the proliferation of murine NIH3T3 cells, so as to provide a theoretical basis for cell tracing technology. METHODS: NIH3T3 cells were cultured in vitro, and were randomly divided into control, pLEGFP-N1 (with transfection of pLEGFP-N1 retroviral vector), pEGFP-N1 (with transfection of pEGFP-N1 vector) and pDsRed2-C1 (with transfection of pDsRed2-C1 vector) groups. Then the cells were screened by G418 for 3 weeks. The changes in cell adhesive rate were observed and the population doubling times was determined by growth curve. RESULTS: There was obvious fluorescent protein expression in the transfected NIH3T3 cells after G418 selection, and the highest percentage of labeled NIH3T3 cells was found in pLEGFP-N1 group. The population doubling time in pDsRed2-C1 (40.3+/-0.7 h) , PEGFP-N1 (39.6 +/- 0.6 h) and pLEGFP-N1 (36.5 +/- 0.7 h) groups was evidently longer than that in control (27.9 +/- 0.6 h, P < 0.01), with high adhesive rate in each group. CONCLUSION: The expression of fluorescent protein exhibited some inhibitory effect on the proliferation of NIH3T3 cells in vitro. Since the inhibitory effect by retroviral vector was weaker compared with eukaryotic vector, it should be the first choice for fluorescent protein labeling during cell transplantation.

Animals↗

PubMed2005

[Tongue image color recognition in traditional Chinese medicine].

The problem of color recognition of substances and coats in tongue images was decomposed into two steps, i. e. region separation and color recognition. In the first step, a new method based on the JSEG and the k-NN algorithms was proposed to separate coats and substances, where a prior template and some standard color patches were designed to assist the classification. Color recognition in a fine scale was carried out by the nearest neighbour method on the basis of the first step. The experiments showed the method proposed in this paper was simple and highly robust, and can be applied to tongue characterization effectively. In addition, the two important preprocessing algorithms namely color calibration and segmentation of tongue images were improved to obtain better results than the former.

Color↗

PubMed2005

[Image segmentation in tongue characterization].

Tongue diagnosis is one of the essential methods of traditional Chinese medical diagnosis. The accuracy of tongue diagnosis can be improved by tongue characterization. Tongue area segmentation and homogeneous regions segmentation in tongue are important contents of preprocess of tongue image. An algorithm based on edge detection and Gradient vector flow (GVF) active contour for tongue area segmentation and another algorithm based on unsupervised segmentation of color-texture for homogeneous regions segmentation in tongue were presented. Totally about 1500 tongue images were collected. Results of tongue area segmentation achieved accuracy rate of 94.3% and results of homogeneous regions segmentation in tongue were approved by traditional Chinese medical experts. The experiments results show robustness of the algorithms. This work establishes solid foundation for feature selecting of Tongue diagnosis.

Algorithms↗

PubMed2004

Homopolymer tract length dependent enrichments in functional regions of 27 eukaryotes and their novel dependence on the organism DNA (G+C)% composition.

BACKGROUND: DNA homopolymer tracts, poly(dA).poly(dT) and poly(dG).poly(dC), are the simplest of simple sequence repeats. Homopolymer tracts have been systematically examined in the coding, intron and flanking regions of a limited number of eukaryotes. As the number of DNA sequences publicly available increases, the representation (over and under) of homopolymer tracts of different lengths in these regions of different genomes can be compared. RESULTS: We carried out a survey of the extent of homopolymer tract over-representation (enrichment) and over-proportional length distribution (above expected length) primarily in the single gene documents, but including some whole chromosomes of 27 eukaryotics across the (G+C)% composition range from 20 - 60%. A total of 5.2 x 10(7) bases from 15,560 cleaned (redundancy removed) sequence documents were analyzed. Calculated frequencies of non-overlapping long homopolymer tracts were found over-represented in non-coding sequences of eukaryotes. Long poly(dA).poly(dT) tracts demonstrated an exponential increase with tract length compared to predicted frequencies. A novel negative slope was observed for all eukaryotes between their (G+C)% composition and the threshold length N where poly(dA).poly(dT) tracts exhibited over-representation and a corresponding positive slope was observed for poly(dG).poly(dC) tracts. Tract size thresholds where over-representation of tracts in different eukaryotes began to occur was between 4 - 11 bp depending upon the organism (G+C)% composition. The higher the GC%, the lower the threshold N value was for poly(dA).poly(dT) tracts, meaning that the over-representation happens at relatively lower tract length in more GC-rich surrounding sequence. We also observed a novel relationship between the highest over-representations, as well as lengths of homopolymer tracts in excess of their random occurrence expected maximum lengths. CONCLUSIONS: We discuss how our novel tract over-representation observations can be accounted for by a few models. A likely model for poly(dA).poly(dT) tract over-representation involves the known insertion into genomes of DNA synthesized from retroviral mRNAs containing 3' polyA tails. A proposed model that can account for a number of our observed results, concerns the origin of the isochore nature of eukaryotic genomes via a non-equilibrium GC% dependent mutation rate mechanism. Our data also suggest that tract lengthening via slip strand replication is not governed by a simple thermodynamic loop energy model.

AT Rich Sequence↗

PubMed2004

Biomaterial surface-dependent neutrophil mobility.

Compromised neutrophil function in the presence of an implanted biomaterial may represent an important mechanism that allows for the development of implant-associated infections. Here, human neutrophil mobility has been investigated on a polyurethane (ChronoFlex AR), a hydrophobic surface consisting of an octadecyltrichlorosilane (OTS) self-assembled monolayer, and a glass reference material. Neutrophil mobility was quantified, based on cell movement speed and persistence time obtained from time-lapse optical microscopy, while neutrophil cytoskeletal structures and morphology were visualized using confocal microscopy and atomic force microscopy. Our results show that material surface properties affect neutrophil-surface interactions, as reflected by morphological changes, and the mobility of neutrophils stimulated by N-formylmethionyl-leucyl-phenylalanine (fMLP). In the absence of adsorbed plasma proteins, the mobility of stimulated neutrophils increased with increasing material hydrophobicity from glass, to polyurethane, to OTS. The opposite trend was observed in the presence of adsorbed plasma proteins, such that neutrophil mobility increased with decreasing material hydrophobicity. Analysis of the results showed that the mobility of fMLP-stimulated neutrophils cells was inversely related to the extent of cell spreading on the materials.

Biocompatible Materials↗

PubMed2004

Human papillomavirus 16 E6 oncoprotein interferences with insulin signaling pathway by binding to tuberin.

Tuberous sclerosis complex (TSC) is a genetic disorder caused by mutations in either TSC1 or TSC2 tumor suppressor gene. TSC1 and TSC2 products, Harmatin and Tuberin, form the functional complex to serve as the negative regulator for insulin-induced phosphorylation of S6 kinase and elF4E-binding protein 1. High-risk human papillomavirus (HPV) infection is the necessary cause for cervical cancer. E6 oncoprotein encoded by HPV plays a pivotal role in carcinogenesis by interference with the host intracellular protein functions. In this study, we show that HPV16 E6 interacts with tumor suppressor gene TSC2 product, Tuberin, and results in the phosphorylation of S6 kinase and S6 even in the absence of insulin. The overexpression of Tuberin overcomes the effect of E6 on S6 kinase phosphorylation. Binding with HPV16 E6 causes the proteasome-mediated degradation of Tuberin. A DILG motif and an ELVG motif located in the carboxyl-terminal of Tuberin are required for E6 binding. In addition, the Tuberin interaction region in E6 has been mapped in the amino-terminal portion of HPV16 E6, which is different from the binding domain with p53. These results provide a possible link between E6-induced oncogenesis and the insulin-stimulated cell proliferation signaling pathway.

Animals↗

PubMed2004

Characterization of plutonium aerosol collected during an accident.

This study determined the plutonium particle size distribution and dissolution rate of PuO2 aerosol collected during the 16 March 2000 release of an undetermined amount of PuO2 in a room within a plutonium facility at Los Alamos National Laboratory. The facility has been in operation since 1978 to support the development, fabrication, and testing of Pu heat sources for the U.S. Department of Energy. Several workers were in the room at the time of the release and in vivo study of five of the workers began the day after the exposure event. Four of the subjects subsequently received chelation therapy. Over 30 fixed air filter samplers (FASs) and four continuous air monitors (CAMs) were operating in the room during the radiological release. One 47-mm-diameter glass fiber FAS filter and one 25-cm-diameter mixed cellulose ester CAM filter containing Pu aerosol from the incident were examined in the study described here. Total alpha radioactivity on the filters was determined by gross alpha counting. Isotopic identification of the Pu was made by alpha spectrometry. Film autoradiography was used to characterize the spatial distribution of alpha-emitting particles on the filters. Track-etch autoradiography was used to estimate the distribution of alpha radioactivity in individual plutonium particles on the filters for particle size measurement. The glass fiber filter was then cut into six sections. Particles from two sections were resuspended in alcohol, dispersed as an aerosol using a Lovelace nebulizer, and characterized by aerodynamic diameter using a Lovelace Multi-jet cascade impactor. The measured activity median aerodynamic diameter from the cascade impactor was 4.8 mum with a geometric standard deviation of 1.5. That agreed with the size distribution obtained from the alpha track detection technique. The remaining four filter sections were used in an in vitro dissolution study with synthetic serum ultrafiltrate. The retention of undissolved Pu was consistent with a biphasic exponential function. The majority of the Pu dissolved with a half-time of 900 d. The information on particle size distribution and solubility from this study was useful in assigning a radiation dose to the exposed workers, supporting the decision to administer chelation therapy, and providing a model for characterizing accident-associated aerosols in the future.

Aerosols↗

PubMed2004

[Methodological study on digitalization of tongue image in traditional Chinese medical diagnosis].

This is a research aimed at proposing a computerized tongue analysis method based on computerized image processing for quantizing the tongue properties in traditional Chinese medical diagnosis. The chromatic algorithm and 2-D Gabor wavelet transformation are applied to segmenting tongue from original image. The statistical method is adopted in identifying the colors of each pixel, which are attributed to the tongue substance and coating respectively. Thickness of tongue coating is determined by energy of 2-D Gabor wavelet coefficients (GWTE). The distribution of GWTE and invariant moment algorithm are used to judge the tongue texture. The experiment result shows that all methods proposed in this paper are effective.

Algorithms↗

PubMed2004

[Synthesis and luminescence properties of reactive ternary europium complexes].

In this paper, five new reactive ternary europium complexes were synthesized with the first ligand of 1,10-phenanthroline and the reactive second ligands of maleic anhydride, acrylonitrile, undecenoic acid, oleic acid and linoleic acid, and also characterized by means of elemental analysis, EDTA titrimetric method, FTIR spectra and UV spectra. The fluorescence spectra show that the five new ternary complexes have much higher luminescence intensity than their corresponding binary complexes, and the synergy ability sequence of the five reactive ligands is as follows: linoleic acid > oleic acid > acrylonitrile > maleic anhydride > undecenoic acid. At the same time, the reactive ternary europium complexes coordinated with the reactive ligands, which can be copolymerized with other monomers, will provide a new way for the synthesis of bonding-type rare earth polymer functional materials with excellent luminescence properties.

English Abstract↗

PubMed2003

Two-phase chemically defined culture system for preimplantation rat embryos.

A limiting factor in the development of new technologies and transport of rats worldwide has been the inability to robustly culture preimplantation embryos. Previously, culture in vitro to the blastocyst stage from one-cell embryos was successful only if the one-cell embryos were isolated near the time of the first cleavage and from only a few strains. Here we report the use of commonly available, chemically defined culture media to overcome these limitations. In vitro culture of young one-cell embryos using common embryo media (KSOM, BMOC, or HTF) for 18-22 h followed by culture in mR1ECM medium allows the successful in vitro development of blastocysts from one-cell embryos after 5 days from both outbred (SD) and inbred strains of rat (WF, LEW, F344, and PVG). This system allows the parthenogenetic development of chemically activated, unfertilized oocytes to the blastocyst stage. Embryos cultured in this system develop to term and are live-born following transfer to surrogate mothers.

Animals↗

PubMed2002

Dose estimate of inhaled hafnium tritide using the ICRP 66 lung model.

Metal tritide is widely used for research, purification, compression, and storage of tritium. The current understanding of metal tritide and its radiation dosimetry for internal exposure is limited, and ICRP publications do not provide the tritium dosimetry for hafnium tritide. The current radiation protection guidelines for metal tritide particles (including hafnium tritide) are based on the assumption that their biological behavior is similar to tritiated water, which is completely absorbed by the body. However, the solubility of metal tritide particles depends on the chemical form of the material. The biological half-live of hafnium tritide particles and the dosimetry of an inhalation exposure to those particles could be quite different from tritiated water. This paper describes experiments on the dissolution rate of hafnium tritide particles in a simulated lung fluid. The results showed that less than 1% of the tritium was dissolved in the simulated lung fluid for hafnium tritide particles after 215 d. The short-term and long-term dissolution half times were 46 and 4.28 x 10(5) d, respectively. This indicates that hafnium tritide is an extremely insoluble material. Self-absorption of beta rays in the hafnium tritide particles was estimated by a numerical method. The dose coefficients were calculated as a function of particle size using in vitro solubility data and a calculated self-absorption factor. The dose coefficient decreased with aerodynamic diameters in the range of 0.25 to 10 microm, mainly because the self-absorption factor decreased with increasing particle size. For a particle 1 microm in aerodynamic diameter, the dose coefficient of a hafnium tritide particle was about 10 times higher than that of tritiated water but was about 1.4 times lower than that calculated by ICRP Publication 71 for Type S tritiated particles. The ICRP estimate did not include a self-absorption factor and thus might have overestimated the dose. This finding has significant implications for current health protection guidelines.

Air Pollutants, Radioactive↗