Biomedical subjects

L Huang

Publications and source records attributed to L Huang.

At least 19 recordsLinked to original sources

PubMed2007

The clinical value of follow-up examinations in childhood T-cell acute lymphoblastic leukemia and T-cell non-Hodgkin's lymphoma.

BACKGROUND: The aim of this study was to evaluate the value of follow-up investigations of T-cell acute lymphoblastic leukemia (T-ALL) and T-cell non-Hodgkin's lymphoma (T-NHL), including cerebrospinal fluid (CSF) examination, bone marrow (BM) aspiration, peripheral blood (PB) count, serum lactate dehydrogenase (LDH) and chest X-rays in patients with an initial mediastinal enlargement. PROCEDURE: We reviewed clinical records of all T-ALL patients from 1987 to 2002 and all T-NHL patients from 1977 to 2002, seen at a single institution. RESULTS: Of 48 T-ALL patients, 15 suffered from a relapse, 6 (40%) were asymptomatic at the time of relapse. T-ALL (13/30) with mediastinal enlargement at first diagnosis relapsed versus 2/16 of those without mediastinal enlargement. However, at relapse, only one patient had a mediastinal mass, which in addition was symptomatic. Of 39 T-NHL patients, 6 patients relapsed. Forty percent of relapsed T-ALL and 17% of relapsed T-NHL were asymptomatic. The seven asymptomatic relapses were detected by CSF (n = 4), BM (n = 2) or blood count (n = 1) examinations. All T-ALL and T-NHL patients with a mediastinal relapse were symptomatic. CONCLUSIONS: This study suggests that routine CSF examinations during treatment can detect relapses of T-ALL and T-NHL before onset of symptoms, which might be of clinical value. Relapses are rarely detected by BM or blood examinations and whether this translates in a clinical benefit is unlikely. Routine chest X-rays are not useful.

Adolescent↗

PubMed2006

Fifth-order Raman spectroscopy of liquid benzene: experiment and theory.

The heterodyned fifth-order Raman response of liquid benzene has been measured and characterized by exploiting the passive-phase stabilization of diffractive optics. This result builds on our previous work with liquid carbon disulfide and extends the spectroscopy to a new liquid for the first time. The all-parallel and Dutch Cross polarization tensor elements are presented for both the experimental results and a finite-field molecular dynamics simulation. The overall response characteristics are similar to those of liquid carbon disulfide: a complete lack of signal along the pump delay, an elongated signal along the probe delay, and a short-lived signal along the time diagonal. Of particular interest is the change in phase between the nuclear and electronic response along the probe delay and diagonal which is not seen in CS2. Good agreement is achieved between the experiment and the finite-field molecular dynamics simulation. The measurement of the low-frequency Raman two-time delay correlation function indicates the intermolecular modes of liquid benzene to be primarily homogeneously broadened and that the liquid loses its nuclear rephasing ability within 300 fs. This rapid loss of nuclear correlations indicates a lack of modal character in the low-frequency motions of liquid benzene. This result is a validation of the general nature of the technique and represents an important step forward with respect to the use of nonlinear spectroscopy to directly access information on the anharmonic motions of liquids.

Journal Article↗

PubMed2006

Tandem chromosome fusions in karyotypic evolution of Muntiacus: evidence from M. feae and M. gongshanensis.

The muntjacs (Muntiacus, Cervidae) are famous for their rapid and radical karyotypic diversification via repeated tandem chromosome fusions, constituting a paradigm for the studies of karyotypic evolution. Of the five muntjac species with defined karyotypes, three species (i.e. Muntiacus reevesi, 2n = 46; M. m. vaginalis, 2n = 6/7; and M. crinifrons, 2n = 8/9) have so far been investigated by a combined approach of comparative chromosome banding, chromosome painting and BAC mapping. The results demonstrated that extensive centromere-telomere fusions and a few centric fusions are the chromosomal mechanisms underlying the karyotypic evolution of muntjacs. Here we have applied the same approach to two additional muntjac species with less well-characterized karyotypes, M. feae (2n = 14 male ) and M. gongshanensis (2n = 8 female). High-resolution G-banded karyotypes for M. feae and M. gongshanensis are provided. The integrated analysis of hybridization results led to the establishment of a high-resolution comparative map between M. reevesi, M. feae, and M. gongshanensis, proving that all tandem fusions underpinning the karyotypic evolution of these two muntjac species are also centromere-telomere fusions. Furthermore, the results have improved our understanding of the karyotypic relationships of extant muntjac species and provided compelling cytogenetic evidence that supports the view that M. crinifrons, M. feae, and M. gongshanensis should each be treated as a distinct species.

Animals↗

PubMed2006

Transcatheter closure of patent ductus arteriosus with severe pulmonary arterial hypertension in adults.

BACKGROUND: Surgical closure of patent ductus arteriosus (PDA) with severe pulmonary arterial hypertension in adults carries higher risk than in children. OBJECTIVES: To investigate the application of self-expandable occluders for transcatheter closure of PDA associated with severe pulmonary arterial hypertension in adults, and the assessment of immediate and short-term results. METHODS: 29 adult patients (6 men, 23 women) underwent attempted transcatheter closure of PDA at a mean (standard deviation (SD)) age of 31.1 (11.4) years (range 18-58 years) and a mean (SD) weight of 54.1 (7.1) kg (range 42-71 kg). On the basis of haemodynamic and clinical data obtained before and after trial occlusion, the final duct occlusion was determined and carried out. Radiographs of the chest, electrocardiograms and echocardiograms were used for follow-up evaluation of the treatment within 1 day, 1 month and 3-6 months after successful closure. RESULTS: 20 of the 29 patients had successful occlusion (group 1), and 9 patients failed (named group 2). In group 1, in which occlusion was successful, mean (SD) pulmonary arterial pressures decreased markedly after trial occlusion: 78 (19.3) mm Hg (range 50-125 mm Hg) before occlusion and 41 (13.8) mm Hg (range 23-77 mm Hg) after occlusion. Systemic arterial oxygen saturation was found to be >90% in 19 patients and <90% in the remaining patient before inhalation of oxygen, and >95% during inhalation of oxygen or after occlusion in all 20 patients. In group 2, the occlusion was not successful, because in two patients the device was not available; another two patients showed worsening of symptoms. The other five patients showed increased pulmonary arterial pressures after trial closure; their mean (SD) pulmonary arterial pressures increased by 10.3 (6) mm Hg (4-16 mm Hg) after trial occlusion, and systemic arterial oxygen saturation was 85.5% (2.6%) (range 82.6-88%) before inhalation of oxygen and 94.7% (1.7%) (range 90.7-99.1%) during inhalation of oxygen. In group 1, the dimensions of the left atrium, left ventricle and pulmonary artery increased considerably in 3-6-months of follow-up compared with those of preocclusion. CONCLUSIONS: Transcatheter closure is an effective treatment for adults with PDA associated with reversible severe pulmonary arterial hypertension. Further research is needed for the evaluation of long-term results.

Adolescent↗

PubMed2006

Observation of two new N* peaks in J/psi-->ppi-n and ppi+n decays.

The decay J/psi-->NNpi provides an effective isospin 1/2 filter for the piN system due to isospin conservation. Using 58x10(6) J/psi decays collected with the Beijing Electromagnetic Spectrometer at the Beijing Electron Positron Collider, more than 100 thousand J/psi-->ppi-n+c.c. events are obtained. Besides the two well-known N* peaks at around 1500 MeV/c2 and 1670 MeV/c2, there are two new, clear N* peaks in the ppi invariant mass spectrum around 1360 MeV/c2 and 2030 MeV/c2 with statistical significance of 11sigma and 13sigma, respectively. We identify these as the first direct observation of the N*(1440) peak and a long-sought missing N* peak above 2 GeV/c2 in the piN invariant mass spectrum.

Journal Article↗

PubMed2006

Intravenously administered oligonucleotides can be delivered to conducting airway epithelium via the bronchial circulation.

Topical gene transfer to the airways of cystic fibrosis (CF) patients has been inefficient, partly due to extracellular barriers such as sputum. In an attempt to circumvent these, we assessed whether airway epithelial cells can be transfected by intravenous (i.v.) administration of liposome-complexed or "naked" oligonucleotides (ODNs). The conducting airways are the likely target for CF therapy and are supplied by the bronchial circulation. Consequently, we assessed ODN transfer in the mouse trachea and main bronchi as these are supplied by the bronchial circulation. Liposome-protamine-DNA (LPD) complexes were detected in the bronchial circulation but did not transfect conducting airway epithelial cells, even in the presence of microvascular leakage. In contrast, 'naked' ODNs were delivered to 17% (inter-quartile range (IQR) 10-34%) and 35% (IQR 24-59%) of epithelial cells when injected at 500 microg/animal, without and with microvascular leakage, respectively. Two types of nuclear signal were observed; punctate in cells throughout the airways (3%, IQR 2-6%, and 6%, IQR 4-7%, of cells when delivered without and with microvascular leakage, respectively) and diffuse in a small number of epithelial cells in the proximal trachea. ODNs may be relevant to CF in a variety of ways and these data suggest one way towards implementing their use.

Animals↗

PubMed2006

Unique role of SNT-2/FRS2beta/FRS3 docking/adaptor protein for negative regulation in EGF receptor tyrosine kinase signaling pathways.

The membrane-linked docking protein SNT-2/FRS2beta/FRS3 becomes tyrosine phosphorylated in response to fibroblast growth factors (FGFs) and neurotrophins and serves as a platform for recruitment of multiple signaling proteins, including Grb2 and Shp2, to FGF receptors or neurotrophin receptors. We previously reported that SNT-2 is not tyrosine phosphorylated significantly in response to epidermal growth factor (EGF) but that it inhibits ERK activation via EGF stimulation by forming a complex with ERK2. In the present report, we show that expression of SNT-2 suppressed EGF-induced cell transformation and proliferation, and expression level of SNT-2 is downregulated in cancer. The activities of the major signaling molecules in EGF receptor (EGFR) signal transduction pathways, including autophosphorylation of EGFR, were attenuated in cells expressing SNT-2 but not in cells expressing SNT-2 mutants lacking the ERK2-binding domain. Furthermore, SNT-2 constitutively bound to EGFR through the phosphotyrosine binding (PTB) domain both with and without EGF stimulation. Treatment of cells with MEK inhibitor U0126 partially restored the phosphorylation levels of MEK and EGFR in cells expressing SNT-2. On the basis of these findings, we propose a novel mechanism of negative control of EGFR tyrosine kinase activity with SNT-2 by recruiting ERK2, which is the site of negative-feedback loop from ERK, ultimately leading to inhibition of EGF-induced cell transformation and proliferation.

Adaptor Proteins, Signal Transducing↗

PubMed2006

Gene therapy progress and prospects: non-viral gene therapy by systemic delivery.

Non-viral vectors continue to be an attractive alternative to viral vectors due to their safety, versatility and ease of preparation and scale-up. Over the past few years, investigators have been successful in developing gene carriers that can be targeted to the disease site. Several different delivery vectors for systemic use have been developed by different groups for plasmid DNA and oligonucleotide. Most of them are designed for targeted tumor therapy. The mechanism of inflammatory toxicity, the major toxicity of cationic lipoplex, has been studied and managed. In this review, we focus on the progress made over the last 2 years. We also discuss some future prospects for gene delivery.

DNA↗

PubMed2006

Serum lipids in the GENECARD study of coronary artery disease identify quantitative trait loci and phenotypic subsets on chromosomes 3q and 5q.

Coronary artery disease (CAD) and dyslipidemia have strong genetic components. Heterogeneity complicates evaluating genetics of complex diseases such as CAD; incorporating disease-related phenotypes may help reduce heterogeneity. We hypothesized that incorporating lipoproteins in a study of CAD would increase the power to map genes, narrow linkage peaks, identify phenotypic subsets, and elucidate the contribution of established risk factors to genetic results. We performed ordered subset analysis (OSA) and quantitative trait linkage (QTL) using serum lipoproteins and microsatellite markers in 346 families with early-onset CAD. OSA defined homogeneous subsets and calculated lod scores across a chromosome after ranking families by mean lipoprotein values. QTL used variance components analysis. We found significantly increased linkage to chromosome 3q13 (LOD 5.10, p = 0.008) in families with higher HDL cholesterol, lower LDL and total cholesterol, lower triglycerides, and fewer CAD risk factors, possibly due to a concentrated non-lipoprotein-related genetic effect. OSA identified linkage on chromosome 5q34 in families with higher cholesterol, possibly representing a hereditary lipoprotein phenotype. Multiple QTLs were identified, with the strongest for: total cholesterol on chromosome 5q14 (LOD 4.3); LDL on 20p12 (LOD 3.97); HDL on 3p14 (LOD 1.65); triglycerides on 18q22 (LOD 1.43); and HDL/TC ratio on 3q27-28 (LOD 2.06). Our findings suggest the presence of etiologic heterogeneity in families with early-onset CAD, potentially due to differential effects of lipoprotein phenotypes. Candidate genes are under investigation.

Adult↗

PubMed2005

Development of an inverse method to identify the kinetics of heavy metal release during waste incineration in fluidized bed.

This paper deals with the emission of heavy metals (HM) during the incineration of municipal solid waste in a fluidized bed reactor. This study focused on the development of a general method to identify the kinetics of vaporization of heavy metals from the on-line analysis of exhaust gas. This method is an inverse method, which requires only the time evolution of the HM concentration in exhaust gases (experimental data) and a global bubbling bed model developed for transient conditions at the reactor scale. First, a lab-scale fluidized bed incinerator was set-up to simulate the HM release during the thermal treatment of metal-spiked model wastes. A specific on-line analysis system based on ICP-OES was developed to measure in real time the variation of the relative concentration of HM in exhaust gases. Then, a two-phase flow bubbling bed model was developed and validated to calculate the kinetics of vaporization of HM from its measured concentration time profile in the outlet gas. The technique was first validated with model waste (metal-spiked mineral matrices), thus enabling at each time both solid sampling for measuring the HM vaporization kinetic and on-line analysis for measuring the HM concentration in the outlet gas. The inverse method was then applied to realistic artificial wastes (derived from real wastes) to identify the HM vaporization kinetics from the on-line analysis results.

Aluminum Oxide↗

PubMed2005

Defining the orientation of the tandem fusions that occurred during the evolution of Indian muntjac chromosomes by BAC mapping.

The Indian muntjac (Muntiacus muntjak vaginalis) has a karyotype of 2n=6 in the female and 7 in the male, the karyotypic evolution of which through extensive tandem fusions and several centric fusions has been well-documented by recent molecular cytogenetic studies. In an attempt to define the fusion orientations of conserved chromosomal segments and the molecular mechanisms underlying the tandem fusions, we have constructed a highly redundant (more than six times of whole genome coverage) bacterial artificial chromosome (BAC) library of Indian muntjac. The BAC library contains 124,800 clones with no chromosome bias and has an average insert DNA size of 120 kb. A total of 223 clones have been mapped by fluorescent in situ hybridization onto the chromosomes of both Indian muntjac and Chinese muntjac and a high-resolution comparative map has been established. Our mapping results demonstrate that all tandem fusions that occurred during the evolution of Indian muntjac karyotype from the acrocentric 2n=70 hypothetical ancestral karyotype are centromere-telomere (head-tail) fusions.

Animals↗

PubMed2005

Stable superhydrophobic surface via carbon nanotubes coated with a ZnO thin film.

We report the formation of a stable superhydrophobic surface via aligned carbon nanotubes (CNTs) coated with a zinc oxide (ZnO) thin film. The CNT template was synthesized by chemical vapor deposition on an Fe-N catalyst layer. The ZnO film, with a low surface energy, was deposited on the CNT template by the filtered cathodic vacuum arc technique. Contact angle measurement reveals that the surface of the ZnO-coated CNTs is superhydrophobic with water contact angle of 159 degrees . Unlike the uncoated CNTs surface, the ZnO-coated CNTs surface shows no sign of water seepage even after a prolonged period of time. The wettability of the surface can be reversibly changed from superhydrophobicity to hydrophilicity by alternation of ultraviolet (UV) irradiation and dark storage.

Hydrophobic and Hydrophilic Interactions↗

PubMed2005

Preparation of supported mesoporous thin films concerning template removal by supercritical fluid extraction.

Thin films of silicate MCM-41 and silicate MCM-48 have been prepared on porous ceramic supports by the hydrothermal method. A comparative study of template removal has been made on supported thin films and on powder. By supercritical fluid extraction (SFE) with CH(3)OH-modified CO(2), at least 78% of the template can be removed from as-synthesized materials at 85 degrees C. X-ray diffraction (XRD) observations indicate that the resulting supported thin films after SFE are structurally stable and ordered with a weak pore contraction. The advantages of SFE over calcination in template removal are presented with a series of results obtained on supported thin films and on powder by XRD and N(2) adsorption-desorption.

Letter↗

PubMed2005

Glial cell line-derived neurotrophic factor (GDNF) is required for differentiation of pontine noradrenergic neurons and patterning of central respiratory output.

Genetic mutations affecting signaling by glial cell line-derived neurotrophic factor (GDNF) perturb development of breathing in mice and are associated with congenital central hypoventilation syndrome in humans. However, the role of GDNF in development of brainstem neurons that control breathing is largely unknown. The present study demonstrates that genetic loss of GDNF decreases the number of tyrosine hydroxylase (TH) neurons in the pontine A5 noradrenergic cell group, a major source of inhibitory input to the medullary respiratory pattern generator. This phenotype is associated with a significant increase in the frequency of central respiratory output recorded from the fetal medulla-spinal cord in vitro. In dissociate cultures of the A5 region from rat embryos, GDNF increases TH cell number and neurite growth without affecting total neuronal survival or proliferation of TH neurons. These effects of GDNF are inhibited by function blocking antibodies against endogenous brain-derived neurotrophic factor (BDNF), indicating that GDNF requires BDNF as a cofactor to stimulate differentiation of A5 neurons. Our findings demonstrate that GDNF is required for development of pontine noradrenergic neurons in vivo and indicate that defects in the A5 cell group may contribute to the effects of genetic disruption of GDNF signaling on respiratory control.

Age Factors↗

PubMed2005

Mechanism of efficient transfection of the nasal airway epithelium by hypotonic shock.

The main barrier to gene transfer in the airway epithelium is the low rate of apical endocytosis limiting naked DNA uptake. Deionized water is known to stimulate the exocytosis of numerous intracellular vesicles during hypotonic cell swelling, in order to expand plasma membrane and prevent cell lysis. This is followed by the phase of regulatory volume decrease (RVD), during which the excess plasma membrane is retrieved by intensive endocytosis. Here we show that the more hypotonic the DNA solution, the higher the transfection of the nasal tissue. P2 receptors are known to be involved in RVD and we demonstrate that some P2 agonists and a P2 antagonist impair transfection in a time-dependent manner. Our study strongly suggests that the nasal airway epithelial cells take up plasmid DNA in deionized water during RVD, within approximately half an hour. Our simple gene delivery system may constitute a promising method for respiratory tract gene therapy.

Animals↗

PubMed2005

An in situ single-pass perfusion model for assessing absorption across the intestinal mucosa of the brushtail possum.

AIM: To develop an in situ animal model for assessing absorption of molecules across the intestinal mucosa of possums. METHODS: A surgical preparation was used to perfuse known concentrations of reference compounds (fluorescein and luteinising hormone-releasing hormone; LHRH) through measured sections of selected regions (jejunum, caecum, proximal colon) of the intestinal tract of 19 possums, over a 2-h period. Plasma concentrations of the compounds, which were perfused either with or without co-administration of a permeation enhancer (sodium deoxycholic acid; SDA), were determined in the perfusion effluent, peripheral and in some instances in the pre-hepatic circulation by spectrofluorometry (fluorescein) or radioimmunoassay (LHRH). Pharmacokinetic parameters of both compounds in the possum were determined over a period of up to 4 h in a further 30 animals (fluorescein, n = 6; LHRH n = 24), from their plasma profiles following intravenous (I/V) administration of a bolus dose. RESULTS: In animals perfused with 25 mg/ml fluorescein (Perfusion Experiment (PE) 1), the mean plasma concentration was 2.8 (SE 0.12) microg/ml in post-hepatic blood samples. When possums were perfused with 2.5 mg/ml fluorescein and 7 microg/ml LHRH (PE 2), mean plasma concentrations were 0.3 (SE 0.01) and 7.8 (SE 1.64) microg/ml fluorescein and 0.1 (SE 0.02) and 6.3 (SE 0.45) ng/ml LHRH, in the absence and presence of permeation enhancer, respectively. There was a poor correlation between pre-hepatic and post-hepatic concentrations. CONCLUSIONS: The single-pass in situ perfusion technique provided a useful model for investigating basic information on the absorption of biocontrol agents across the intestinal tract of possums, but had limitations that must be recognised.

Animals↗

PubMed2005

Microwave tumour coagulation plus in situ treatment with cytokine-microparticles: induction of potent anti-residual tumour immunity.

After local microwave coagulation and subsequent intra-tumoural injection of microparticles encapsulating interleukin-2 and granulocyte-macrophage colony-stimulating factor, the anti-tumour efficacy against subcutaneous Lewis lung carcinoma in syngeneic mice was evaluated. This treatment elicited a potent systemic anti-tumour immunity that protected treated mice from re-challenge with the same tumour cells and caused the distal tumours in a bilateral tumour model to be rejected. Cytotoxicity assay indicated that both T- and natural killer cells acted as the effector cells in the anti-tumour immunity. These data highlight the feasibility of microwave-pre-treated in situ cancer vaccination for clinical use.

Animals↗

PubMed2005

Electrogastrography in neonates.

BACKGROUND AND AIMS: Procedures for diagnosis of gastrointestinal (GI) symptoms in newborn and preterm infants should preferably be non-invasive. This study evaluates the usability of electrogastrography (EGG), a non-invasive, cutaneous recording of the gastric myoelectrical activity in newborn infants. METHOD: Sixty-two randomly selected infants [27 girls and 35 boys with median gestational age of 36 weeks (range 29-42)] divided into six groups (by postconceptional age) were studied on median day 5 (range 1-24) after birth. None had GI symptoms. EGG recordings were made by Digitrapper EGG recording system. RESULTS: Findings were highly dispersed and without statistical difference both between pre- and postprandial periods and among the six study groups. Dominant frequency of 2.5 cycles per minute was found for 57 of 62 infants, with distribution of normal, bradygastric and tachygastric slow wave frequency uniformly dispersed around 50, 35 and 15% respectively. CONCLUSION: We find EGG unsuitable for clinical use because of significant variation in gastric slow wave frequency in normal term and preterm infants without GI symptoms.

Electrodiagnosis↗