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H Wang

Publications and source records attributed to H Wang.

At least 217 records · Page 12Linked to original sources
PubMed2003

Mathematical theory of molecular motors and a new approach for uncovering motor mechanism.

Molecular motors operate in an environment dominated by thermal fluctuations. A molecular motor may produce an active force at the reaction site to directly move the motor forward. Alternatively a molecular motor may generate a unidirectional motion by rectifying thermal fluctuations. In this case, the chemical reaction establishes free energy barriers to block the backward fluctuations. The effect of the chemical reaction on the motor motion can be represented by the motor potential profile (rectifying barrier andor active driving force). Different motor mechanisms are characterised by different motor potential profiles. The mathematical theory and properties of molecular motors are discussed and a mathematical framework is developed for extracting the motor potential profile from measured time series of motor position. As an example, we discuss the binding zipper model for the F(1) ATPase, which was motivated mainly by the fact that the motor potential profile of the F(1) ATPase is nearly a constant slope.

Journal Article↗
PubMed2003

Discovering molecular pathways from protein interaction and gene expression data.

In this paper, we describe an approach for identifying 'pathways' from gene expression and protein interaction data. Our approach is based on the assumption that many pathways exhibit two properties: their genes exhibit a similar gene expression profile, and the protein products of the genes often interact. Our approach is based on a unified probabilistic model, which is learned from the data using the EM algorithm. We present results on two Saccharomyces cerevisiae gene expression data sets, combined with a binary protein interaction data set. Our results show that our approach is much more successful than other approaches at discovering both coherent functional groups and entire protein complexes.

Algorithms↗
PubMed2003

Long term visual outcome of patients with cytomegalovirus retinitis treated with highly active antiretroviral therapy.

BACKGROUND: Healed cytomegalovirus (CMV) retinitis in the setting of highly active antiretroviral therapy (HAART) is complicated by inflammatory sequelae and vision loss. AIM: To determine the long term visual outcome of AIDS patients with CMV retinitis who received HAART. METHODS: 90 eyes of 63 consecutive AIDS patients with extramacular CMV retinitis were studied prospectively. RESULTS: Immune recovery status was related to time to onset of epiretinal membrane (p=0.05) and cystoid macular oedema (p=0.06) as well as to the incidence of cataract (p=0.001) and moderate vision loss (p<0.0001). Severe vision loss was associated with retinal detachment (p<0.001). CONCLUSION: AIDS patients with extramacular CMV retinitis lose vision while on HAART. HAART related immune recovery is associated with increased frequencies of epiretinal membrane, cystoid macular oedema, cataract, and retinal detachment with resultant vision loss in AIDS patients with healed CMV retinitis.

AIDS-Related Opportunistic Infections↗
PubMed2003

Decreased neutrophil apoptosis in tracheal fluids of preterm infants at risk of chronic lung disease.

OBJECTIVE: To investigate the hypothesis that preterm infants who are more susceptible to lung damage have decreased neutrophil apoptosis, and to explore its relation to interleukin 10 (IL10) concentration. DESIGN: Prospective cohort design. PATIENTS: One hundred tracheal fluid specimens from 50 week-1 ventilated infants were examined for IL10 (by enzyme linked immunosorbent assay) and neutrophil apoptosis (by light microscopy). RESULTS: Neutrophil apoptosis was absent or less than 0.22% (median 0%) in the 11 infants with chronic lung disease (CLD) (24-31 weeks gestation) during the first 4 days of life. This was significantly lower than that of the 20 preterm infants without CLD (27-31 weeks gestation; median 0.47%, range 0-1.25%) and 19 term infants (median 0.5%, range 0-2.25%). There was an increase in apoptosis in infants with CLD (median 0.44%, p = 0.046) during days 5-7. Few infants without CLD were intubated beyond 4 days. Median apoptosis on days 5-7 was 0.26% and 2.78% for non-CLD preterm and term infants, but differences were not significant. IL10 concentration in tracheal fluid of infants with CLD was less than 5 pg/ml. None of the infants with IL10 greater than 5 pg/ml developed CLD. The range of IL10 concentrations in tracheal fluid from infants without CLD was wide (0-938 pg/ml). There was no apparent correlation between IL10 levels and percentage neutrophil apoptosis in infants without CLD. CONCLUSION: Preterm infants with low levels of IL10 and neutrophil apoptosis may be predisposed to disordered lung repair. Further studies into the method of disposal of senescent neutrophils within preterm lungs are required.

Apoptosis↗
PubMed2003

Assessment of the impact of the removal of cerebrospinal fluid on cerebral tissue volumes by advanced volumetric 3D-MRI in posthaemorrhagic hydrocephalus in a premature infant.

Current clinical practice in the premature infant with posthaemorrhagic ventricular dilatation (PHVD) includes drainage of cerebrospinal fluid (CSF). This case study used advanced volumetric three dimensional magnetic resonance imaging to document the impact of CSF removal on the volume of regional brain tissues in a premature infant with PHVD. The removal of a large volume of CSF was associated with an identical reduction in CSF volume, but more dramatically with a significant increase in the regional volumes of cortical grey matter and myelinated white matter. The alterations in cerebral cortical grey matter and myelinated white matter volumes may provide insight into the established association of PHVD with deficits in cognitive and motor functions.

Brain↗
PubMed2003

Expression profile of mRNAs from human pancreatic islet tumors.

In order to understand the tIssue specificity of the endocrine pancreas, it is important to clarify the expression profile of mRNAs in various states of the tIssue. A total of approximately 9000 non-redundant expressed genes from human pancreatic islets and insulinoma have so far been determined as expressed sequence tags (ESTs) and deposited in public databases. In the present study towards the identification of a complete set of genes expressed in human pancreatic islets, we have determined 3'-ESTs of 21267 clones randomly selected from a cDNA library of human pancreatic islet tumors. Clustering analysis generated 6157 non-redundant sequences comprising 2323 groups and 3834 singletons. Nucleotide and peptide database searches show that 3103 of them represent known human sequences or homologs of genes identified in other species and 58 are new members of structurally related families. The sequences were classified on the basis of the putative protein functions encoded, and were assigned to the respective chromosome by database analysis. The sequences were also compared with the EST databases (dbEST and EPConDB) including ESTs from normal pancreatic islet, insulinoma, and fetal pancreas. Since 3384 genes were newly found to be expressed in human pancreatic islets and 587 of them were unique to the islets, this study has considerably expanded the catalog of genes expressed in the endocrine pancreas. The larger collection of pancreatic islet-related ESTs should provide a better genome source for molecular studies of differentiation, tIssue-specific functions, and tumorigenesis of the endocrine pancreas as well as for genetic studies of diabetes mellitus.

Cloning, Molecular↗
PubMed2003

Physical and processing properties of milk, butter, and cheddar cheese from cows fed supplemental fish meal.

Physical, chemical, sensory and processing properties of milk produced by feeding a rumen-undegradable fish meal protein supplement to Holstein cows were investigated. The supplement contained (as fed basis) 25% soft-white wheat, 60% herring meal, and 15% feather meal. The total fat level in the milk decreased to 2.43%. For both pasteurized and ultra-high temperature processed drinking milk, no difference was found between fish meal (FM) milk and control milk in terms of color, flavor and flavor stability; in particular, no oxidized flavor was observed. Cheddar cheese made from FM milk ripened faster after 3 mo of ripening and developed a more desirable texture and stronger Cheddar flavor. The yield efficiencies for FM and control cheese, 94.4 (+/- 2.44 SE) and 96.4 (+/- 2.26 SE), respectively, were not different. Relative to controls, average fat globule size was smaller in FM milk and churning time of FM cream was longer. FM butter had softer texture and better cold spreadability, and butter oils from FM enriched milk had lower dropping points compared to control butter oil (average 32.89 versus 34.06 degrees C). These differences in physical properties of butter fat were greater than expected considering that iodine values were not different. This study demonstrates the feasibility of producing high quality products from milk naturally supplemented with FM, but the results also show that dietary changes affect processing properties.

Animal Feed↗
PubMed2003

Analysis of lewis antigens on cell surface and alpha1,3 fucosyltransferase subtypes in H7721 human hepatocarcinoma cells.

The expressions of Lewis antigens on H7721 human hepatocarcinoma cells were detected with monoclonal antibodies and flow-cytometry. It was found that H7721 mainly expressed SLex, and a small amount of SDLex, but Lex and SLea was negligible. The monoclonal antibody of SLex (KM93) significantly blocked the adhesion of H7721 cells to human umbilical vein epithelial cells, as well as cell migration and invasion, but the blocking effect of SDLex antibody (FH6) was not statistically significant. The expressions of five subtypes of alpha1,3fucosyltransferases (alpha1,3FucTs), the enzyme responsible for the fucosylation step in Lewis antigen synthesis, were also studied using real-time RT-PCR. The expression of FucT mRNAs were FucT-IV > FucT-III > FucT-VI > or = FucT-VII > FucT-IX. FucT-VI is supposed to be the main enzyme responsible for the synthesis SLex and SDLex. FucT-VII and III may also participate in SLex synthesis. The absence of FucT-IX expression and FucT-III not being the rate-limiting enzyme for SLea synthesis may be the reasons for the negligible expressions of Lex and SLea on the cell surface, respectively.

Antibodies, Monoclonal↗
PubMed2003

Acceleration of callus maturation using rhOP-1 in mandibular distraction osteogenesis in a rat model.

The aim of this study was to assess if the application of rhOP-1 induces accelerated consolidation of the callus in mandibular distraction osteogenesis. In seven adult Wistar rats a bilateral osteotomy of the horizontal ramus of the mandible was performed in the molar region and a custom designed distractor was mounted to the mandible. With a rate of 0.7 mm per day the device was activated bilaterally after the seventh postoperative day. After seven days of distraction two times 50 microg rhOP-1 were injected on two subsequent days directly into the callus. The contralateral side received an injection of placebo solution. The animals were killed four weeks after the end of distraction. A three-point bending test revealed a significantly higher strength of the distracted mandible in the rhOP-1 side (66.3 N vs. 30.4 N, P=0.034, paired t-test). Undecalcified histological sections were examined using microradiography and fluorescence microscopy after sequential intravital polychromic labelling. A continuous bony bridging was seen in all rhOP-1 sites and in none of the control sites. The data indicate that rhOP-1 may be an option to accelerate callus maturation in mandibular distraction osteogenesis.

Animals↗
PubMed2003

Echinococcosis on the Tibetan Plateau: prevalence and risk factors for cystic and alveolar echinococcosis in Tibetan populations in Qinghai Province, China.

Infections by larval stages of tapeworms of the genus Echinococcus (echinococcosis or hydatid disease) are zoonotic infections of major public health importance throughout much of the world. Humans become infected through accidental ingestion of eggs passed in faeces of canid definitive hosts. Tibetan populations of China have some of the highest documented levels of infections by both Echinococcus granulosus and E. multilocularis, the causes of cystic and alveolar echinococcosis, respectively. In this study we measured the prevalence of cystic (CE) and alveolar (AE) echinococcosis disease in Tibetan communities in Qinghai, Province, China, and identified putative risk factors for both infections in these communities. 3703 volunteers in three predominately Tibetan counties of Qinghai were surveyed between June 1997 and June 1998. Parasitic lesions were diagnosed by imaging of characteristic space-occupying lesions in abdominal organs (ultrasound) or the lungs (radiographs). Specific serodiagnostic assays (Dot-ELISA and Em2-ELISA) were performed on sera of positively imaged subjects to further distinguish the disease agent. All participants completed a questionnaire documenting age, sex, education level, occupation, lifestyle (nomadic or settled), slaughter practices, drinking water source, hygienic practice and association with dogs. Data were analyzed using SAS version 8. 6.6% of the volunteers had image-confirmed infection with E. granulosus (CE) and 0.8% had E. multilocularis (AE) infection. The significant univariate factors for echinococcal infection (both CE and AE) included livestock ownership, Tibetan ethnicity, female gender, low income, herding occupation, limited education, water source, age greater than 25 years old, poor hygienic practices, offal disposal practices and dog care. Multivariate analysis revealed that livestock ownership was a significant risk factor for both forms of the disease, as well as age greater than 25 years, female gender, herding occupation, and being nomadic (vs semi-nomadic or settled). No additional significant risk factors were identified among the 344 nomadic participants. Being female and being older than 25 years of age were significant factors among the 1906 semi-nomadic participants. Among the 1445 settled participants, allowing dogs to sleep indoors was statistically significant. Issues such as inadequate assessment of animal ownership, selection bias, disease misclassification, and loss of information may have led to reduction in strength of some risk factor associations and need to be addressed in future epidemiologic analysis of echinococcosis in this population.

Adolescent↗
PubMed2002

Endocannabinoid signaling in synchronizing embryo development and uterine receptivity for implantation.

There are reports of adverse effects of cannabinoids on pregnancy outcome including retarded embryo development and pregnancy failure. Thus, discoveries of endogenous cannabinoid-like lipid mediators and cannabinoid receptors raise questions about their pathophysiological roles during normal pregnancy. We previously reported that anandamide, an endogenously produced arachidonate derivative (endocannabinoid), is synthesized in the female reproductive tracts, and it acts on cannabinoid receptors expressed on the cell surface of the embryo to regulate the preimplantation embryo development and implantation in mice. This review presents genetic, molecular, physiological and pharmacological evidence that the levels of uterine anandamide and blastocyst CB1 cannabinoid receptors are coordinately regulated to synchronize preimplantation development and uterine receptivity for implantation in mice.

Animals↗
PubMed2002

Interstitial microdeletion of chromosome 1p in two siblings.

Two half-siblings are described with what we believe to be the second and third cases identified of the microdeletion, del(1)(p32.1p32.3). Both siblings had a tethered cord and had mental retardation, but otherwise their phenotypic presentations were quite different. The sister had failure to thrive, congenital dysplasia of the hip, absent corpus callosum, Chiari I malformation, and syringomyelia. The brother experienced neonatal seizures secondary to a hemorrhagic stroke. He had an accessory thumb, inguinal hernia, cryptorchidism, urinary reflux, and cholelithiasis. Although these children have only delayed development in common with the previously reported case, they help to further define chromosomal deletions in this area of chromosome 1. As yet, no clear phenotypic picture has emerged.

Adolescent↗
PubMed2002

O 1s --> sigma* resonance in O2: inadequacy of only two exchange-split components.

The O 1s-->sigma* transition below the O K-edge in O2 has been investigated by absorption, constant ionic state (CIS) experiments, and extensive configuration interaction calculations. CIS scans of the three lowest-lying final states reached in resonant Auger decay provide a wealth of information on energy range, symmetry, and spin multiplicity of the intermediate states with sigma* character. We conclude that the identification of only two exchange-split components is inadequate because a complex manifold of states with sigma* character exists with no unique energy difference between related states.

Journal Article↗