Biomedical subjects

C Huang

Publications and source records attributed to C Huang.

At least 19 recordsLinked to original sources

PubMed2007

Bacterial inactivation using a low-temperature atmospheric plasma brush sustained with argon gas.

This study investigated the bacterial inactivation/sterilization effects of a new atmospheric plasma source, which is a brush-shaped argon glow discharge created under 1 atm pressure. Such an atmospheric plasma brush requires extremely low power of less than 20 W to operate; and therefore is essentially a low-temperature discharge as confirmed by gas-phase temperature measurements. Two bacteria, Escherichia coli (E. coli) and Micrococcus luteus (M. luteus), seeded in various media were subjected to plasma treatment and their survivability was examined. It was found that such argon atmospheric plasma brush is very effective in destruction of the bacteria cells. With nutrient broth and standard methods agar as supporting media, a cell reduction in a level of 6 orders of magnitude was observed for E. coli within 3-4 min plasma treatment. A similar level of cell reduction was also observed for M. luteus in the two media with 2 or 3 min plasma treatment. The plasma treatment effects on the bacteria cell structures were also examined using scanning electron microscopy and the cell structure damages due to the plasma exposure were observed on both bacteria. The possible sterilization mechanism of the argon plasmas is also discussed in this article.

Argon↗

PubMed2006

Positron production by x rays emitted by betatron motion in a plasma wiggler.

Positrons in the energy range of 3-30 MeV, produced by x rays emitted by betatron motion in a plasma wiggler of 28.5 GeV electrons from the SLAC accelerator, have been measured. The extremely high-strength plasma wiggler is an ion column induced by the electron beam as it propagates through and ionizes dense lithium vapor. X rays in the range of 1-50 MeV in a forward cone angle of 0.1 mrad collide with a 1.7 mm thick tungsten target to produce electron-positron pairs. The positron spectra are found to be strongly influenced by the plasma density and length as well as the electron bunch length. By characterizing the beam propagation in the ion column these influences are quantified and result in excellent agreement between the measured and calculated positron spectra.

Journal Article↗

PubMed2006

HIV infection changes glomerular podocyte cytoskeletal composition and results in distinct cellular mechanical properties.

In addition to forming the selective filtration barrier for the renal glomerulus, podocytes maintain glomerular capillary architecture by opposing distending hemodynamic forces. To understand the relationship of cytoskeletal properties and the mechanical characteristics of podocytes, we studied filamin expression and distribution and measured cell membrane deformability in conditionally immortalized wild-type (WT) mouse podocytes, and in podocytes derived from a mouse model of HIV-associated nephropathy (HIVAN). In the WT cells, filamin and F-actin were localized at the periphery and in prominent stress fibers. In the HIVAN cells, filamin expression was reduced, and stress fibers were sparse. In a microaspiration assay, HIVAN cells ruptured under minimal negative pressure. Atomic force microscopy demonstrated that the WT cells had a stiffness of 17 kPa, whereas the value for the HIVAN cells was 4 kPa. These results demonstrate that the mechanical properties of WT and HIVAN podocytes are markedly different in a manner that is consistent with differences in the composition and arrangement of their cytoskeletons. The mechanical properties of the WT podocytes suggest that these cells can better maintain capillary integrity than the HIVAN podocytes and implicate pathological assembly of the cytoskeleton as a mechanism of HIVAN.

Actinin↗

PubMed2006

Stability of E-cadherin methylation status in gastric mucosa associated with histology changes.

BACKGROUND: We have previously shown reversal of E-cadherin methylation in gastric mucosa from patients with dyspepsia at week 6 after Helicobacter pylori-eradication therapy. But the long-term methylation status of these patients was unknown. AIM: To investigate the methylation status at E-cadherin at year 3 after H. pylori-eradication therapy. METHODS: 35 patients (25 with and 10 without H. pylori eradicated) enrolled in our previous study were recruited into the present study (year 3 analysis). Methylation at E-cadherin was evaluated by methylation-specific polymerase chain reaction method. RESULTS: There was no difference in age and sex distribution in the two groups. Methylation at E-cadherin in patients with H. pylori eradicated at weeks 0, 6 and year 3 were 52%, 20% and 20%, respectively. Concordant methylation status at week 6 and year 3 was 92%. Methylation at E-cadherin in patients without H. pylori at weeks 0, 6 and year 3 were 50%, 60% and 60%, respectively. Concordant methylation status between week 6 and year 3 was 90%. Stability of E-cadherin methylation status was associated with histological changes. No association between E-cadherin methylation status and age was observed. CONCLUSION: The methylation pattern is stable for a long period, thus suggesting the effect of environment on methylation.

Anti-Bacterial Agents↗

PubMed2006

Evaluations of biomarkers associated with 5-FU sensitivity for non-small-cell lung cancer patients postoperatively treated with UFT.

The sensitivity to 5-fluorouracil (5-FU) has been reported to be associated with target molecule thymidylate synthase (TS), fluoropyrimidine-metabolising enzymes such as orotate phosphoribosyltransferase (OPRT), and dihydropyrimidine dehydrogenase (DPD). We performed an immunohistochemical study on the clinical significance of TS, OPRT, and DPD expression using 151 resected non-small-cell lung cancer (NSCLC) patients postoperatively treated with a combination of tegafur and uracil (UFT). Eighty-two carcinomas were TS-positive, 105 carcinomas were OPRT-positive, 68 carcinomas were DPD-positive. No correlation was observed in the HSCORE between the TS and OPRT expression (r=0.203), between the TS and DPD expression (r=0.098), or between the OPRT and DPD expression (r=0.074). Regarding the survival of NSCLC patients treated with UFT, the 5-year survival rate of patients with TS-negative tumours was significantly higher than that with TS-positive tumours (P=0.0133). The 5-year survival rate of patients with OPRT-positive stage II to III tumours was significantly higher than that with OPRT-negative stage II to III tumours (P=0.0145). In addition, the 5-year survival rate of patients with DPD-negative tumours was also significantly higher than that with DPD-positive tumours (P=0.0004). A Cox multivariate regression analysis revealed the TS status (hazard ratio 2.663; P=0.0003), OPRT status (hazard ratio 2.543; P=0.0005), and DPD status (hazard ratio 2.840; P<0.0001) to all be significant prognostic factors for the survival of resected NSCLC patients postoperatively treated with UFT.

Adult↗

PubMed2006

Nonlinear theory for relativistic plasma wakefields in the blowout regime.

We present a theory for nonlinear, multidimensional plasma waves with phase velocities near the speed of light. It is appropriate for describing plasma waves excited when all electrons are expelled out from a finite region by either the space charge of a short electron beam or the radiation pressure of a short intense laser. It works very well for the first bucket before phase mixing occurs. We separate the plasma response into a cavity or blowout region void of all electrons and a sheath of electrons just beyond the cavity. This simple model permits the derivation of a single equation for the boundary of the cavity. It works particularly well for narrow electron bunches and for short lasers with spot sizes matched to the radius of the cavity. It is also used to describe the structure of both the accelerating and focusing fields in the wake.

Journal Article↗

PubMed2006

Experimental determination of the helium-metal interaction potential by interferometry of nanostructured surfaces.

We present a direct experimental comparison of the helium-surface interaction potential for two unreconstructed metal surfaces. We analyze phase shifts in helium atom scattering from a nanostructured bimetallic surface to yield the relative shape and position of an adsorbate's potential with respect to the reference defined by the substrate. In our prototype system, submonolayer growth of Ni on Cu(100), the He-Ni/Cu(100) potential has an attractive well that is 1.6+/-0.4 meV shallower, and a repulsive wall 0.11+/-0.03 A closer to the ion cores, compared to the He-Cu(100) potential. Our observations provide a ready test of state-of-the-art theoretical calculations.

Journal Article↗

PubMed2006

Dredging of drainage ditches increases short-term transport of soluble phosphorus.

Managed drainage ditches are common in the midwestern United States. These ditches are designed to remove water from fields as quickly as possible, and sediment buildup necessitates dredging, to ensure adequate water removal. This laboratory study was conducted to determine the impact of ditch dredging on soluble phosphorus (P) transport. Ditch sediments were collected from a drainage ditch in northeastern Indiana immediately before and after dredging. The sediments were placed in a stream simulator, and stream water was loaded with 0.55 mM P for 5 d (adsorption experiment). Water was then removed, and "clean" water (no P added) was used for a desorption experiment, lasting 1 d. During the adsorption experiment, pre-dredged sediments were able to remove P from the water column quicker, and P concentrations 120 h after introduction of high P water were lower for the pre-dredged sediments (0.075 mM P) than the dredged sediments (0.111 mM P). During the desorption experiment, P was released to the water column slower in the pre-dredged treatment than the dredged treatment (instantaneous flux at t = 0 was 0.205 microM P h(-1) for pre-dredged and 0.488 microM P h(-1) for dredged). This occurred despite higher Mehlich 3-extractable P in the pre-dredged sediments than the dredged sediments. Equilibrium phosphorus concentrations (EPCo) were lower in the pre-dredged sediments during both adsorption and desorption experiments. Transport of soluble P immediately after dredging will likely increase in drainage ditches; however, dredging is a necessary management tool to ensure adequate discharge of water from surrounding fields.

Adsorption↗

PubMed2006

Hose instability and wake generation by an intense electron beam in a self-ionized gas.

The propagation of an intense relativistic electron beam through a gas that is self-ionized by the beam's space charge and wakefields is examined analytically and with 3D particle-in-cell simulations. Instability arises from the coupling between a beam and the offset plasma channel it creates when it is perturbed. The traditional electron hose instability in a preformed plasma is replaced with this slower growth instability depending on the radius of the ionization channel compared to the electron blowout radius. A new regime for hose stable plasma wakefield acceleration is suggested.

Journal Article↗

PubMed2006

The HAUSP gene plays an important role in non-small cell lung carcinogenesis through p53-dependent pathways.

Herpesvirus-associated ubiquitin-specific protease (HAUSP) directly stabilizes the tumour suppressor p53 by de-ubiquitination. Therefore, the HAUSP gene might play an important role in carcinogenesis. In this paper, HAUSP expression and p53 gene status have been studied in relation to the expression of p53 target genes in 131 patients with non-small cell lung cancer (NSCLC). p53 gene status was evaluated by polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) followed by sequencing. Quantitative reverse-transcription polymerase chain reaction (RT-PCR) was performed to evaluate the gene expression of HAUSP, p21, and bax. Immunohistochemistry was performed to evaluate the protein expression of p53, HAUSP, mdm2, p21, and bax. Fifty-nine carcinomas (45.0%) showed reduced expression of HAUSP, and 58 carcinomas (44.3%) had mutations of p53. Concerning tumour histology, HAUSP mRNA expression was significantly lower in adenocarcinomas than in squamous cell carcinomas (p = 0.0038), while the frequency of p53 mutation was significantly higher in squamous cell carcinomas than in adenocarcinomas (p = 0.0461). There was no significant difference in HAUSP mRNA expression according to p53 gene status. In total, 93 carcinomas (71.0%) showed either mutant p53 or reduced HAUSP expression. The down-regulation of HAUSP was associated with reduced p53 protein expression (p = 0.0593 in tumours with wild-type p53 and p = 0.0004 in tumours with mutant p53). Furthermore, p21 and bax protein expression was significantly lower in tumours with either mutant p53 or reduced HAUSP expression than in tumours with both wild-type p53 and positive HAUSP expression (p = 0.0440 and p = 0.0046, respectively). In addition, the simultaneous evaluation of both HAUSP expression and p53 gene status was a significant indicator of poor prognosis in adenocarcinoma patients (hazard ratio 4.840, p = 0.0357). These results suggest that reduction of HAUSP gene expression may play an important role in NSCLC carcinogenesis, especially in adenocarcinomas, through p53-dependent pathways.

Carcinoma, Non-Small-Cell Lung↗

PubMed2006

Diagnostic accuracy of contrast-enhanced ultrasound in focal lesions of the liver using cadence contrast pulse sequencing.

UNLABELLED: The purpose of this study was to assess the accuracy of Cadence Contrast Pulse Sequencing (Siemens-Acuson, CA) method with injection of SonoVue (Bracco Imaging SpA, Italy) for the detection and characterisation of focal liver lesions in comparison with a reference modality during routine use. METHODS: 138 consecutive patients (62 women, 76 men; mean age: 52 years for women and 63 years for men) corresponding to 144 examinations with 381 lesions participated in this prospective study from December 2002 to November 2003. Inclusion criteria were lesions detected by conventional US and the availability of a reference imaging examination (CT or MR imaging) within three weeks. The underlying liver lesions characterised by a reference modality (including biopsy in 29 lesions) were distributed as follows: haemangioma (n = 56), focal nodular hyperplasia (n = 27), hepatocellular carcinoma (n = 44), hepatocellular adenoma (n = 5), liver metastasis (n = 174), abscess (n = 2), cysts (n = 45), other benign lesions (n = 24) and 3 peritoneal metastases. RESULTS: A significant improvement was reported in the number of detected lesions between contrast-enhanced ultrasound and baseline ultrasonography (351 lesions versus 280 lesions, respectively, p < 0.01), whereas no significant difference was noted between contrast-enhanced ultrasound and reference imaging (351 versus 377 lesions, respectively). On the whole, contrast-enhanced ultrasound allowed a complete diagnosis in 96 % of the detected nodules with a significant improvement compared to conventional sonography in which the diagnosis was suspected in only 52 % out of these cases (p < 0.001). No significant difference was noted between contrast-enhanced ultrasound and the reference modality concerning characterisation of nodules. CONCLUSION: The present study clearly indicates that contrast-enhanced sonography using Sonovue and Cadence Contrast Pulse Sequencing allows real-time imaging with high accuracy and thus will be a competitive alternative to other modalities such as CT and MR imaging for liver imaging.

Adult↗

PubMed2006

Improvement in glycaemic control with rosiglitazone/metformin fixed-dose combination therapy in patients with type 2 diabetes with very poor glycaemic control.

OBJECTIVE: Traditional first-line intervention in patients with type 2 diabetes and very poor glycaemic control is insulin therapy or high doses of sulfonylureas if there is no evidence of volume depletion. This study explored the safety and efficacy of open-label treatment with rosiglitazone and metformin (RSG/MET) fixed-dose combination therapy (AVANDAMET) in patients with type 2 diabetes with very poor glycaemic control, to better characterize the magnitude of glycated haemoglobin (A1c) reduction after 24 weeks of therapy. METHODS: In this multicentre, open-label trial, 190 patients with an A1c greater than 11% or fasting plasma glucose (FPG) greater than 15 mmol/l were included after failing to meet glycaemic entry criteria for a primary double-blind, controlled, randomized study. Unless tolerability issues arose, eligible patients initiated RSG/MET 4 mg/1000 mg fixed-dose combination therapy and were up-titrated in increments of 2 mg/500 mg at 4-week intervals to a daily dose of 8 mg/2000 mg or the maximum tolerated dose. Patients were assessed for efficacy and safety at five visits over a 24-week period. The primary efficacy end point was change from baseline in A1c at week 24. Secondary efficacy end points included the proportion of patients achieving defined A1c targets, change from baseline to week 24 in FPG and insulin sensitivity. RESULTS: The majority of patients (78%) completed 24 weeks of open-label treatment. At week 24, clinically significant mean reduction in A1c from 11.8 to 7.8% (mean reduction, 4.0 +/- 2.2%; p < 0.0001) and mean FPG reduction from 16.9 to 9.2 mmol/l (mean reduction, 7.7 +/- 4.4 mmol/l; p < 0.0001) were observed. A clinically significant reduction in FPG (5.2 mmol/l) was observed after 4 weeks of treatment with RSG/MET fixed-dose combination therapy. Despite a high mean baseline A1c of 11.8%, 33% of patients achieved treatment goal of A1c less than or equal to 6.5% at week 24, and 44% achieved an A1c less than 7% at week 24. RSG/MET fixed-dose combination was well tolerated, with a low incidence of hypoglycaemia (2%) and mean increase in weight from baseline of 2.6 +/- 5.2 kg, and few patients withdrew (2.6%) because of an adverse event. CONCLUSIONS: RSG/MET fixed-dose combination therapy was effective as initial therapy in patients with type 2 diabetes and very high levels of A1c and/or FPG, as demonstrated by robust and relatively rapid improvements in glycaemic control. RSG/MET fixed-dose combination was well tolerated as first-line therapy with no new tolerability issues identified.

Adolescent↗

PubMed2006

Association of intercellular adhesion molecule 1 polymorphisms with retinopathy in Chinese patients with Type 2 diabetes.

AIMS: To investigate the relationship of the K469E and G241R polymorphisms of the intercellular adhesion molecule 1 (ICAM-1) gene with diabetic retinopathy in Chinese patients with Type 2 diabetes mellitus. PATIENTS AND METHODS: One hundred and seventy-two Chinese patients with Type 2 diabetes and 80 normal control subjects were recruited. Patients with diabetes were placed into two groups: the diabetic retinopathy (DR) group and the non-diabetic retinopathy (NDR) group. The DR group was subdivided into those with proliferative retinopathy (PDR) and non-proliferative retinopathy (NPDR). Genomic DNA was prepared using the hydroxybenzene-chloroform extraction method. Genotypes and alleles were detected by polymerase chain reaction-heteroduplex-single-strand conformation polymorphism (PCR-HA-SSCP) analysis combined with gene sequencing. RESULTS: The patients with retinopathy had an increased frequency of the K469K genotype compared with both the patients without retinopathy and the control subjects (61.4 vs. 40.0 and 35.0%, respectively; chi(2) = 8.280 and 13.952, respectively; P < 0.05). The frequency of the K allele in the DR group was higher than in the NDR group and control subjects (75.4 vs. 58.8 and 61.3%, respectively; chi(2) = 9.693 and 11.219, respectively; P < 0.05). Genotype and allele frequencies were similar in the NDR group and control subjects, and in the PDR and NPDR groups. CONCLUSION: The ICAM-1 gene K469E polymorphism is associated with diabetic retinopathy in Chinese patients with Type 2 diabetes. Patients with the K469K genotype were more likely to have diabetic retinopathy than patients with the K469E or E469E genotype.

Adult↗

PubMed2006

Parameter optimization and design aspect for electrocoagulation of silica nano-particles in wafer polishing wastewater.

A systematic procedure has been proposed for the design of a multi-channel, continuous-flow electrocoagulation reactor of mono-polar configuration for the removal of sub-micron particles from wastewater. Using the chemical-mechanical-planarization (CMP) process as the target source of wastewater, a series of laboratory-scale studies were conducted to determine the required operating conditions for the efficient removal of the ultrafine particles. These operating criteria included charge loading (> or = 8 F m(-3)), current density (> or = 5.7 A m(-2)), hydraulic retention time (> or = 60 min), as well as the initially operational pH (7 to approximately 10). Furthermore, a steady-state transport equation with second-order reaction kinetics was employed to describe the rate of coagulation as the rate-limiting factor. The actual kinetic constant determined from the laboratory-scale experiments was approximately 1.2 x 10(-21) m3 s(-1), which was three orders of magnitude smaller than that calculated based on Brownian diffusion during the coagulation. The model was subsequently validated with a series of experiments using a pilot-scale electro-coagulation reactor geometrically similar to the laboratory-scale reactor with nearly twenty times volumetric scale-up.

Bioreactors↗

PubMed2006

[Combined large cell neuroendocrine carcinoma and squamous cell carcinoma of the lung; report of a case].

An 80-year-old man was admitted to our hospital because a routine chest X-ray had revealed a nodular shadow in the right lower lung field. Transbronchial lung biopsy (TBLB) failed to give at definitive diagnosis, therefore open lung biopsy was performed because of suspected lung cancer. Rapid intraoperative pathological examination diagnosed the tumor as large cell carcinoma. However, bloody pleural effusion was classified as class V. It was judged difficult to perform a curative operation, so the operation was interrupted. Pathological diagnosis was combined large cell neuroendocrine carcinoma and squamous cell carcinoma. Pleurodesis was done, and the patient is under observation at 7 months after the operation.

Aged, 80 and over↗

PubMed2005

Multi-GeV energy gain in a plasma-wakefield accelerator.

A plasma-wakefield accelerator has accelerated particles by over 2.7 GeV in a 10 cm long plasma module. A 28.5 GeV electron beam with 1.8 x 10(10) electrons is compressed to 20 microm longitudinally and focused to a transverse spot size of 10 microm at the entrance of a 10 cm long column of lithium vapor with density 2.8 x 10(17) atoms/cm3. The electron bunch fully ionizes the lithium vapor to create a plasma and then expels the plasma electrons. These electrons return one-half plasma period later driving a large amplitude plasma wake that in turn accelerates particles in the back of the bunch by more than 2.7 GeV.

Journal Article↗

PubMed2005

On multiscale approaches to three-dimensional modelling of morphogenesis.

In this paper we present the foundation of a unified, object-oriented, three-dimensional biomodelling environment, which allows us to integrate multiple submodels at scales from subcellular to those of tissues and organs. Our current implementation combines a modified discrete model from statistical mechanics, the Cellular Potts Model, with a continuum reaction-diffusion model and a state automaton with well-defined conditions for cell differentiation transitions to model genetic regulation. This environment allows us to rapidly and compactly create computational models of a class of complex-developmental phenomena. To illustrate model development, we simulate a simplified version of the formation of the skeletal pattern in a growing embryonic vertebrate limb.

Animals↗

PubMed2005

Reduction of insulin-stimulated glucose uptake in L6 myotubes by the protein kinase inhibitor SB203580 is independent of p38MAPK activity.

Insulin increases glucose uptake through translocation of the glucose transporter GLUT4 to the plasma membrane. We previously showed that insulin activates p38MAPK, and inhibitors of p38MAPKalpha and p38MAPKbeta (e.g. SB203580) reduce insulin-stimulated glucose uptake without affecting GLUT4 translocation. This observation suggested that insulin may increase GLUT4 activity via p38alpha and/or p38beta. Here we further explore the possible participation of p38MAPK through a combination of molecular strategies. SB203580 reduced insulin stimulation of glucose uptake in L6 myotubes overexpressing an SB203580-resistant p38alpha (drug-resistant p38alpha) but barely affected phosphorylation of the p38 substrate MAPK-activated protein kinase-2. Expression of dominant-negative p38alpha or p38beta reduced p38MAPK phosphorylation by 70% but had no effect on insulin-stimulated glucose uptake. Gene silencing via isoform-specific small interfering RNAs reduced expression of p38alpha or p38beta by 60-70% without diminishing insulin-stimulated glucose uptake. SB203580 reduced photoaffinity labeling of GLUT4 by bio-LC-ATB-BMPA only in the insulin-stimulated state. Unless low levels of p38MAPK suffice to regulate glucose uptake, these results suggest that the inhibition of insulin-stimulated glucose transport by SB203580 is likely not mediated by p38MAPK. Instead, changes experienced by insulin-stimulated GLUT4 make it susceptible to inhibition by SB203580.

Animals↗