Biomedical subjects

Jian Huang

Publications and source records attributed to Jian Huang.

At least 163 records · Page 9Linked to original sources

PubMed2002

The effects of acute and chronic amiodarone on activation patterns and defibrillation threshold during ventricular fibrillation in dogs.

OBJECTIVES: The goal of this study was to evaluate the effects of acute and chronic amiodarone on activation patterns during ventricular fibrillation (VF), ventricular effective refractory period (VERP) and defibrillation threshold (DFT). BACKGROUND: Acute and chronic amiodarone may act through different mechanisms. METHODS: The VERP, VF activation patterns and DFT were determined in 24 dogs. Twelve dogs received acute intravenous amiodarone (10 mg/kg, n = 6) or saline (n = 6), and 12 dogs received chronic oral amiodarone (20 mg/kg/day, n = 6) or placebo (n = 6). Epicardial VF activation patterns were recorded with 504 electrodes. Quantitative descriptors of VF were calculated. RESULTS: The DFT was unchanged by acute or chronic amiodarone. Although chronic amiodarone significantly extended the VERP, acute amiodarone did not. In the mapped region, acute and chronic amiodarone decreased the number of VF wavefronts by 42% and 60%. Acute amiodarone decreased conduction block by 22%, while chronic amiodarone increased block by 41% but decreased wave fractionation by 50%. Both chronic and acute amiodarone increased the size of the core of re-entrant circuits and decreased the incidence of re-entry by 44% and 57%; however, chronic amiodarone increased wavelength, while acute amiodarone did not. CONCLUSIONS: Neither acute nor chronic amiodarone change the DFT. While both acute and chronic amiodarone decrease the number of wavefronts, decrease the incidence of re-entry and increase the size of re-entrant cores in the mapped region during VF, they achieve these antiarrhythmic effects through different electrophysiologic mechanisms. Chronic amiodarone prolonged the VF cycle length and slowed conduction velocity, indicating it increased the wavelength and/or the excitable gap.

Amiodarone↗

PubMed2002

The first successful base-promoted isomerization of propargyl amides to chiral ynamides. Applications in ring-closing metathesis of ene-ynamides and tandem RCM of diene-ynamides.

[reaction: see text] A highly useful sequence of reactions is described here. These reactions consist of the first successful base-induced isomerizations of propargyl amides to chiral ynamides, applications of these novel ynamides in ring-closure metathesis leading to chiral 2-amidodienes useful for Diels-Alder cycloadditions, and the first successful tandem RCM of diene-ynamides.

Journal Article↗

PubMed2002

Score test for mapping quantitative-trait loci with sibships of arbitrary size when the dominance effect is not negligible.

In the linakge analysis of quantitative traits, an additive model that assumes no dominance effect is often adopted. Intuitively, when the no-dominance-effect assumption does not hold, such a practice does not make efficient use of the data, and its power to detect linkage can be improved. Here we introduce a score statistic for detecting quantitative trait loci when the dominance effect is not neglible or the dominance effect is a concern. This statistic is derived from a normal likelihood function for sibships of arbitrary size. In the derivation, the inherent genetic constraints on model parameters are fully taken into consideration. This score statistic is asymptotically equivalent to the corresponding likelihood ratio statistic, but it is much easier to compute. The asymptotic distribution of this statistic is derived, which is a mixture of chi(0) (2), chi(1) (2), and chi(2) (2). Weights for distribution components are functions of the informativeness of the marker data. The type I error rate and the power of the proposed statistic in finite sample are evaluated via simulations.

Chromosome Mapping↗

PubMed2002

Immortalized chromaffin cells disimmortalized with Cre/lox site-directed recombination for use in cell therapy for pain after partial nerve injury.

To prepare immortalized adrenal chromaffin cells for eventual clinical use, the immortalizing oncogene must be removed. We have utilized a Cre-mediated excision of a loxP-flanked Tag sequence to test whether immortalized chromaffin cells could be disimmortalized by this method. Cultures of embryonic rat adrenal cells were immortalized with the tsA-TN retroviral vector encoding the loxP-flanked temperature-sensitive allele of SV40 large T antigen (tsA-TN) and a positive/negative neo/HSV-TK sequence for selection with either G418 or gancyclovir, respectively. These cells were then infected with the 1710-CrePR1 bicistronic retroviral vector coding for a form of Cre modulatable by the synthetic steroid RU486. These immortalized loxTsTag/CrePR1/RAD cells expressed immunoreactivities (ir) for all the catecholamine enzymes: tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DbetaH), and phenylethanolamine-N-methyltransferase (PNMT). After initial incubation at 37 degrees C with RU486 for 3 days, followed by the addition of gancyclovir for 7 days, Tag-ir was not detectable in most of the surviving chromaffin cells, compared to 100% expression in immortalized loxTsTag/CreR1/RAD cells not treated with RU486 and gancyclovir. The expression of TH, DbetaH, and PNMT was increased after disimmortalization and the ability of disimmortalized cells to synthesize norepinephrine was also significantly increased compared to immortalized cells. When both types of chromaffin cells were transplanted in a model of neuropathic pain and partial nerve injury, both cell grafts were equally able to reverse the behavioral hypersensitivity induced by the injury. The use of Cre/lox site-directed disimmortalization of chromaffin cells that are able to deliver neuroactive molecules offers a novel approach to cell therapy.

Animals↗

PubMed2002

Identification of a NF-kappaB site in the negative regulatory element (epsilon-NRAII) of human epsilon-globin gene and its binding protein NF-kappaB p50 in the nuclei of K562 cells.

The developmental control of the human epsilon-globin gene expression is mediated by transcription regulatory elements in the 5' flanking DNA of this gene. Sequence analysis has revealed a DNA motif (GGGGAATTTGCT) similar to NF-kappaB consensus sequence resides in the negative regulatory element (-3028bp approximately -2902bp, termed e-NRAII) 5' to the cap site of this gene. NRF DNA fragment (-3010bp approximately -2986bp) containing the NF-kappaB motif similar sequence was synthesized and used in electrophoresis mobility shift assay (EMSA) and competitive analysis. Data showed that a protein factor from nuclear extracts of K562 cells specifically interacted with NRF DNA fragment. The synthetic NF DNA fragment (containing NF-kappaB consensus sequence) could competed for the protein binding, but MNF DNA fragment (mutated NF-kappaB motif) could not, suggesting that the binding protein is a member of NF-kappaB/Rel family. Western blot assay demonstrated that the molecular weight of NF-kappaB protein in the nuclei of K562 cells is 50ku. We suggested that NF-kappaB p50 may play an important role in the regulation of human epsilon-globin gene expression.

Base Sequence↗

PubMed2002

Effect of electrode location in great cardiac vein on the ventricular defibrillation threshold.

This study tested the hypothesis that the DFT could be lowered by delivering a weak auxiliary shock in conjunction with a stronger primary shock with the auxiliary shock electrode near the cardiac region where the primary shock electric field is weakest. This hypothesis was tested by determining the DFTs with the auxiliary shock delivered from different locations within the great cardiac vein (GCV). In 15 dogs, catheters with defibrillation electrodes were placed transvenously in the RV apex, the SVC, and the GCV. An active can electrode and the SVC electrodes were electrically coupled to serve as a return electrode for the RV and GCV electrodes. DFTs were determined for a primary shock through the RV electrode with and without a subsequent auxiliary shock of lower amplitude through the GCV electrode. The leading edge voltage and current at DFT were significantly lowered by addition of the auxiliary shock (17% and 19% decreased, respectively), but energy was not changed. The animals were divided into three groups according to the location of the GCV electrode. The leading edge voltage, current, and total delivered energy at the DFT were significantly lower in animals with the GCV electrode near the apex (22%, 24%, and 13% reduction, respectively) compared with those where the GCV electrode was positioned away from apex (8%, 10% reduction and 18% increase, respectively, P < 0.001). Application of an auxiliary shock to the apical region, near the region where previous studies have indicated that the RV primary shock has its weakest effects, caused the greatest decrease in DFT.

Animals↗

PubMed2002

Fiberglass needle electrodes for transmural cardiac mapping.

We developed a new method for fabricating plunge needle electrodes for use in cardiac mapping. The needles have 12 electrodes with 1-mm spacing, are 0.5 mm in diameter, and are fabricated from fiberglass reinforced epoxy. They are stiff enough to be easily inserted into beating hearts and durable enough to be reused many times. We found that these new needles elicit smaller, more quickly resolving injury potentials, and when inserted in a row with 2-mm spacing, disrupt ventricular fibrillation activation patterns less than traditional steel needles.

Animals↗

PubMed2002

Mild hypothermia induced before cardiac arrest reduces brain edema formation in rats.

OBJECTIVES: The mechanisms by which hypothermia improves cardiac arrest (CA)-induced brain damage are unclear. The authors hypothesized that mild hypothermia induced before CA attenuates brain edema formation by preventing neutrophil-mediated dysfunction of the endothelial cell junction proteins. METHODS: Eighteen rats were randomized to normal control surgery (group 1, n = 6), normothermic (37.5 degrees C) CA (group 2, n = 6), or hypothermic (34 degrees C) CA (group 3, n = 6). Hypothermia was induced with external cooling before CA in group 3. Cardiac arrest was induced by 8 minutes of asphyxiation. Brain edema was determined by wet-to-dry weight ratio and cerebral spinal fluid pressure (CSFP). Brain neutrophil content was determined by myeloperoxidase (MPO) activity, and occludin degradation was assessed by western blotting. RESULTS: Normothermic CA significantly increased brain wet-to-dry weight ratio from 4.52 +/- 0.04 in group 1 to 4.80 +/- 0.04 in group 2 (p = 0.0003) and CSFP from 3.6 +/- 0.9 in group 1 to 8.9 +/- 0.9 mm Hg in group 2 (p = 0.004). Mild hypothermia before CA in group 3 significantly reduced brain wet-to-dry weight ratio (4.68 +/- 0.03, p = 0.008 vs. group 2) and CSFP (3.8 +/- 0.5 mm Hg, p = 0.004 vs. group 2). Cardiac arrest increased brain MPO from 0.07 +/- 0.025 in group 1 to 0.16 +/- 0.02 units/gram brain weight in group 2 (p = 0.006) that was not decreased by hypothermia before CA (0.12 +/- 0.02 in group 3 (p = 0.07 vs. group 2). There was no occludin proteolysis in any group. CONCLUSIONS: Mild hypothermia before CA decreases CA-induced brain edema. The hypothermia-elicited reduction in brain edema does not appear to be neutrophil-dependent and the early brain edema formation may not involve the proteolysis of occludin.

Analysis of Variance↗

PubMed2002

Transmural recording of monophasic action potentials.

To investigate the possibility of transmural recording of repolarization through the ventricular wall, KCl monophasic action potential (MAP) electrodes positioned along plunge needles were developed and tested. The MAP electrode consists of a silver wire surrounded by agarose gel containing KCl, which slowly eluted into the adjacent tissue to depolarize it. In six dogs, a plunge needle containing three KCl MAP electrodes was inserted into the left ventricle to simultaneously record from the subepicardium, midwall, and subendocardium. In six pigs, eight plunge needles containing three KCl MAP electrodes and two plunge needles containing similar electrodes except for the absence of KCl were inserted into the ventricles. In three guinea pig papillary muscles, a KCl electrode was used to record MAPs along with two microelectrodes for recording transmembrane potentials. Transmural MAP recordings could be made for >1 h in dogs and >2 h in pigs with a significant decrease in MAP amplitude over time but without a significant change in MAP duration. With the electrodes without KCl in pigs, the injury potentials subsided in <30 min. When the pacing rate was changed to alter the action potential duration and refractory period in dogs, the MAP duration correlated with the local effective refractory period (r = 0.94). The time course of the MAP duration recorded with a KCl MAP electrode in guinea pig papillary muscles corresponded well with that of the transmembrane potential recorded with an adjacent microelectrode. It is possible to record transmural repolarization of the ventricles with KCl MAP electrodes on plunge needles. The MAP is caused by the KCl rather than being a nonspecific injury potential.

Action Potentials↗

PubMed2002

HLA class I expression in primary hepatocellular carcinoma.

AIM: To investigate whether CTL vaccine therapy is suitable for primary hepatocellular carcinoma (HCC) from the viewpoint of HLA class I antigens expression. METHODS: The immunocytochemistry, image analysis, flow cytometry, and labeled streptavidin biotin (LSAB) method of immunohistochemistry were applied respectively to study 4 HCC cell lines (e.g. Alexander, HepG2, SMMC-7721, and QGY-7703) cultured in vitro and 6 frozen tissue specimens of HCC. RESULTS: The positive control cell line Raji had very strong positive staining. Most mitotic and nonmitotic cells of the 4 HCC cell lines had various intensity of HLA class I antigens expression. The negative control cell K562 and the control slides of all the cell lines had no positive staining. In the 6 HCC specimens immunohistochemically studied, histological normal hepatocytes had no or very weak positive staining and the liver sinus had very strong positive staining. Most HCC cells in the sections from the 6 HCC specimens had strong positive HLA classIantigens staining. The positive staining was located in the cytoplasm, the perinuclear area, and at the cell membrane of the liver cancer cells. Flow cytometry also revealed that Raji and those 4 HCC cell lines had strong HLA classIantigens expression, which was confirmed quantitatively by the image analysis. It showed that the objective grayscale values of Raji and those 4 HCC cell lines were significantly different from that of K562 (Raji 114.04+/-10.94, Alexander 165.97+/-5.35, HepG2 167.02+/-12.60, QGY-7703 161.46+/-7.13, SMMC-7721 165.93+/-5.21, K562 244.89+/-4.60, P<0.01). Significant differences were also found between Raji and the 4 HCC cell lines. CONCLUSION: HCC cells express HLA class I antigens strongly. From this point of view, the active specific immunotherapy of CTL vaccine is suitable and practicable for HCC.

Cancer Vaccines↗

PubMed2002

[Immune responses of dendritic cells after loaded with cytotoxicity T lymphocyte epitope based peptide of human alpha-fetoprotein (hAFP)].

OBJECTIVE: To study the immune responses of lymphocytes after activated by dendritic cells (DCs) loaded with cytotoxicity T lymphocyte (CTL) epitope based peptide of human alpha-fetoprotein (hAFP, 218-226 LLNQHACAV). METHODS: Get high purity DCs by cultured plastic-adherent monocytes isolated from healthy donor of HLA-A2(+) peripheral blood with granulocyte-monocyte colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) for 7 days. Stimulate self-lymphocytes with DCs that loaded with CTL epitope based peptide of hAFP under the culture medium contains interleukin-2 (IL-2) for 7 days. Analyse IL-12 and TNF in culture medium and also the specific lysis activity of lymphocytes against four strains of primary hepatocellular carcinoma cells. RESULTS: After stimulated by DC loaded with CTL epitope based peptide derived from hAFP, lymphocytes appeared a good characteristics and the culture medium of activated lymphocytes contained a high level Th1 type cytokines of IL-12 and TNF. Activated lymphocytes not only specifically lysed HLA-A2(+) HepG2 line but also had the cytotoxicity against other three primary hepatocellular carcinoma cell lines and T2 target cell loaded with peptide of hAFP. CONCLUSIONS: The results of this research supply the basic materials for the DC based vaccine with HLA-A2 restricted peptide epitope derived from hAFP against AFP positive primary hepatocellular carcinoma.

Adult↗

PubMed2002

[Preparation and analysis of oligonucleotide microarray for expression detection of mouse cytokine-associated gene].

A new method for the preparation of oligonucleotide microarray for gene expression detection was found. The key techniques and standards of quality controlling for preparation of oligonucleotide microarray was explored using gene of human 23 kD highly protein and Luciferase and mouse cytokine-associated genes. By the using of a software system MProbe, oligonucleotide probes were designed and BLAST. All the probes have a very high specificity, i.e. except target sequence, the similarity between the probe and non-target sequences is less than 70% and the hairpin structure are not exist in all probes. All the probes have the same length 40. GC contents in all probes are in a narrow scope (from 45% to 55%). All the probes are modified with amino at 5' or 3' terminal. The satisfied images with good sensitivity and very high specificity were obtained by the using of the methods above and also using of positive and negative controls and some internal controls(house keeping gene) to quantitate and balance expression of genes. High specificity, good sensitivity and stability have been verified by three continuous experiments using the oligonucleotide microarray to study gene expression profile of normal mouse breast grand tissue. The oligonucleotide microarray for expression detection prepared using our method have high specificity, good sensitivity and stability et al. It may be a more advanced method for analysis of gene expression profile.

Animals↗

PubMed2002

[Clinical observation on adoptive immunotherapy with autologous cytokine-induced killer cells for advanced malignant tumor].

BACKGROUND & OBJECTIVE: Cytokine-induced killer (CIK) cells have the characteristics of rapid proliferation, high efficiency, and broad spectrum in killing of tumor cells. However, there was few report about its clinical application on treatment for cancer patients. The current study was designed to evaluate the effect of adoptive transfer of autologous CIK cells on the patients with advanced malignant tumor. METHODS: Peripheral blood mononuclear cells of the patients with advanced malignant tumor were separated by fractionation on Ficoll-Hypaque gradient, then cultured in the medium containing IFN-gamma, IL-2, and CD3McAb for 7 days in vitro, and than the cultured auto-CIK cells were transfused back to the patients. The numbers of transferred CIK cells per patient were 5-15 x 10(9) in one course of treatment. Among these patients, 47 cases received chemotherapy, 3 cases received radiotherapy before CIK cells transfusion. The interval between chemoradiotherapy and immunotherapy was over 2 to 4 weeks. RESULTS: Among 63 patients receiving CIK cells immunotherapy, the total effective rate (PR + MR) was 44.46% (28). In the patients with increasing of CEA level in serum, 14 cases showed reduction of serum CEA and 1 cases remained increasing after the treatment with CIK cell. In the patients with increasing of AFP level in serum, similarly, 9 cases showed reduction of serum AFD and 1 case remained increasing. The absolute members of CD3, CD4, and CD8T cells increased to over 45% after being treated with CIK cells. Among treated patients, the appetite of 51 cases and performance and sleep of 32 cases got improved. Among 18 cases, 13 cases showed the pain relief. CONCLUSION: Adoptive immunotherapy of auto-CIK cells can significantly enhance cellular immune functions and improve subjective symptoms, but without side effects, so this is a safe and effective treatment for the patients with malignant tumor.

Adult↗

PubMed2002

[Preliminary study on the growth stimulation of marine microalgae stimulated by low level of toxicant].

Cell growth of Nitzschia closterium and Platymonas subcordiformis was stimulated under 4 and 8 micrograms.L-1 anthrancene stress, respectively. The cell growth of two species was also stimulated under 30 mg.L-1 streptomycin stress. The hormesis of marine microalgae cells under low level of anthrancene and streptomycin resulted in low level of free radical and decrease of microorganisms. Furthermore, the hormesis of marine microalgae was also discussed in this paper.

Ecosystem↗

PubMed2002

MProbe: computer aided probe design for oligonucleotide microarrays.

The present work describes a complete probe design software system for oligonucleotide microarrays based on Kane's research on probe sensitivity and specificity (Kane's rule). Combining Kane's rule and traditional criteria for probe design we constructed MProbe, the software system for oligonucleotide microarrays using Java. The general criteria for probe design are: (1) probes may have different lengths that range from 20 to 100 bases; (2) they should have a similar melting temperature (Tm) or GC content; (3) they should not contain stable secondary structures; and (4) they abide by Kane's rule.

Computational Biology↗

PubMed2001

Screening of Genes Related to the Expression of Human epsilon-globin Gene by Using Yeast One-hybrid System.

The developmental stage-specific silencing of the human epsilon-globin gene during embryonic period is controlled, in part, by a silencer (from -392 to -177 bp) upstream of this gene. In our previous work, by using DNase I footprinting assay, a major protected region from -278 to -235 bp within this silencer DNA was identified. In order to isolate genes encoding proteins that bind to this target element, a human fetal liver cDNA library was screened by using yeast one-hybrid system. The candidate clones were sequenced, and the ribosomal protein L3 (RPL3) was preliminarily isolated. Electrophoretic mobility shift assay (EMSA) and competition tests also demonstrated its binding activity to the target element. These imply that RPL3 might play an important role in silencing the human embryonic epsilon-globin gene expression through the interaction with this silencer.

Journal Article↗

PubMed1999

Sequence Analysis of 47 Low-abundance ESTs Expressed in Early Human Embryo.

The availability of high quality cDNA libraries has proven essential to positional gene cloning efforts differential gene expression studies and EST sequencing/mapping projects.In order to isolate and identify new genes expressed during early human development a 3-week-old human embryo cDNA library was constructed and a pre-screening procedure was used to select cDNAs corresponding to low abundance mRNAs. 6 508 clones were hybridized with a mixture of cDNA probes. Approximately 1 677 clones (26%) did not hybridize with the cDNA probes and represent low abundance mRNAs as well as empty vectors.Partial sequences were generated from one or both end of 47 low abundance cDNA clones and the sequences comparisons with genetic databases revealed that 38.3% of them was annotated human genes 10.6% was highly similar to those from either human or other species 40.4% was partial sequence matched with ESTs that had already been detected and 8.5% of the cDNAs appeared to be unknown in the genetic databases.

Journal Article↗

PubMed1999

Construction of Early Human Embryo cDNA Libraries and Screening Objective Genes.

The construction, evaluation, and application of cDNA libraries from 3-, 4-, and 5-week-old human embryos are described. Total RNAs were extracted from whole embryos using a modified single-step method. mRNA purified by two passes through oligo (dT) columns was reverse-transcripted into single-stranded cDNA. Alkaline agarose electrophoresis showed that the double-strand cDNA fragments ranged from 0.4 9.0 kb and most of them were in the range of 1.0 2.0 kb. After separation on SizeSep 400 Spun columns to eliminate excess adaptors and small cDNA fragments(less than 400 bp), the cDNAs were ligated into pSPORT1 plasmid and lambdaZipLox phage. The plasmid libraries have complexities of 2.6x10(5), 1.7x10(5) and 2.1x10(5) clones and the phage cDNA libraries have complexities of 3.4x10(6), 3.7x10(6) and 2.3x10(6) clones, respectively. Three whole length cDNAs encoding human CD59, MCP and DAF were amplified by PCR using 3-week-old phage library as templates, and human tPA gene with whole length cDNA was screened from 4-week-old plasmid library by hybridization. It was shown that these libraries are of high quality and are suitable to screen rarely expressed genes. The libraries are a valuable source for the study of novel gene expression during human development.

Journal Article↗