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S Sun

Publications and source records attributed to S Sun.

At least 19 recordsLinked to original sources
PubMed2006

Development and validation of a real-time Taqman PCR assay for the detection and quantitation of infectious laryngotracheitis virus in poultry.

In this study, the development and validation of a real-time (ReTi) PCR assay is described using a Taqman labeled probe for the detection and quantitation of infectious larygotracheitis virus (ILTV) in chickens. The ReTi ILTV assay was highly specific with a quantitation limit of 100 viral template copies per amplification reaction. In experimentally infected, birds during early acute stages of infection, an average of 6.67 log(10) viral template copies/amplification reaction were detected, while at chronic late stages of infection an average of 2.86-3.27 log(10) viral template copies/amplification reaction were detected. A total of 246 tracheal swab samples collected from natural outbreaks of the disease were tested by virus isolation and the ReTi ILTV assay. Both assays agreed in 37% of the samples tested and the ReTi ILTV assay detected approximately 3.7 times more positives samples than virus isolation. A minimum of 5 log(10) viral template copies/amplification reaction were required from a tracheal swab to render a virus isolation positive result. In conclusion, the ReTi ILTV assay was highly specific, sensitive, reproducible, and capable of reliably quantifying viral nucleic acid directly from clinical samples.

Animals↗
PubMed2006

7beta-hydroxycholesterol reduces the extent of reactive gliosis caused by iron deposition in the hippocampus but does not attenuate the iron-induced seizures in rats.

7beta-Hydroxycholesterol has been previously demonstrated to inhibit astrocytosis in injured cortex or spinal cord of rats. In this study, we explored the inhibitory effects of the liposome containing 7beta-hydroxycholesterol on the reactive astrocytosis caused by the injection of iron into the hippocampus of rats and furthermore evaluated the involvement of reactive astrocytosis in iron-induced epilepsy. Injection of ferric chloride solution unilaterally into the hippocampus of rats induced spontaneous spiking activity ipsilaterally then developed into bilateral hippocampi and generalized convulsive seizures within the first week post-operation, and spontaneous epileptiform activity and generalized seizures lasted as long as 2 weeks post-operation, whereas none of the rats injected with sodium chloride solution unilaterally into the hippocampus developed generalized seizures. With immunohistochemistry and Western blot analyses, apparent reactive astrocytosis in bilateral hippocampi was detected using antibody against glial fibrillary acidic protein 14 days after the injection of ferric chloride solution, but no significant differences were found in the amount of synaptophysin protein, a presynaptic vesicle protein, as compared with the rats injected with sodium chloride solution. Infusion of liposome suspension containing 7beta-hydroxycholesterol into the same site immediately after the injection of ferric chloride solution reduced the extent of the reactive astrocytosis by 50%-55% of the amount of glial fibrillary acidic protein in the hippocampi of both hemispheres, and non-significantly elevated the amount of synaptophysin protein in both sides of hippocampus. However, these effects did not significantly modify the seizure latency and the incidence of generalized seizures in the rats. These findings demonstrate the effects of 7beta-hydroxycholesterol on the inhibition of reactive astrocytosis caused by iron deposition in the hippocampus of rats, and suggest that the reactive astrocytosis may not play a causal role in the development of iron-induced seizures.

Action Potentials↗
PubMed2006

Protective effect of glutathione against lipopolysaccharide-induced inflammation and mortality in rats.

OBJECTIVE: To investigate protective effect of glutathione (GSH) against lipopolysaccharide (LPS)-induced inflammation and mortality in rats. METHODS: Male Sprague-Dawley rats were injected intraperitoneally (i. p.) with GSH (40 mg/kg) 30 min prior to LPS injection (20 mg/kg). Animal survival rate and the production of nitric oxide in serum were measured. Morphology of lung was observed using hematoxylin and eosin staining. Western blotting was used to assess the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and the phosphorylation of p38 in rat peritoneal macrophages. RESULTS: GSH significantly decreased LPS-induced mortality, inhibited serum NO production and eliminated lung histological injury. Furthermore, GSH inhibited the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins and the phosphorylation of p38 in LPS-stimulated rat peritoneal macrophages. CONCLUSIONS: These results indicated that GSH suppressed LPS-induced systemic inflammatory response in rats and p38 MAPK signal pathway was involved in this process.

Animals↗
PubMed2006

Endoscopic ultrasound-guided interstitial brachytherapy of unresectable pancreatic cancer: results of a pilot trial.

BACKGROUND AND STUDY AIMS: Intraoperative interstitial brachytherapy has been found to be effective when used during laparotomy to improve local control in patients with locally advanced pancreatic cancer. In this study, we report the results of using endoscopic ultrasound- (EUS-)guided interstitial brachytherapy in patients with advanced pancreatic cancer, with respect to tumor response, clinical response, safety, and complications. PATIENTS AND METHODS: Fifteen patients (eight men, seven women; median age 61 years) with unresectable pancreatic adenocarcinoma were enrolled into the study, eight patients with stage III disease and seven patients with stage IV disease. A mean number of 22 radioactive seeds per patient were implanted into the tumors by EUS-guided needle puncture. The mean total implanted activity was 20 mCi, the minimum peripheral dose was 14,000 cGy, and the mean volume of implants was 52 cm3. Patients were followed-up by examination and by imaging tests every 2-3 months: clinical end points included the Karnofsky performance status and pain responses, tumor response (assessed by computed tomography and/or EUS), and survival. RESULTS: During a median follow-up period of 10.6 months, the objective tumor response was classified as "partial" in 27% of patients (with a median duration of partial response of 4.5 months), "minimal" in 20% patients, and indicative of "stable disease" in 33% of patients. Clinical benefit was shown in 30% of patients, mostly due to reduction in pain, but this lasted for a limited time. Local complications (pancreatitis and pseudocyst formation) occurred in three patients; grade III hematologic toxicity occurred in three patients without serious clinical sequelae. CONCLUSIONS: EUS-guided intraoperative interstitial brachytherapy had a moderate local tumor effect and showed some clinical benefit in 30% of the patients in this study. Combination of this form of treatment with external radiation and/or chemotherapy should be tested in future trials.

Adenocarcinoma↗
PubMed2006

Effects of a single nucleotide polymorphism on the expression of human tumor necrosis factor-alpha.

Tumor necrosis factor (TNF)-alpha plays a prominent role in inflammations and is a proinflammatory cytokine that has been implicated in the pathogenesis of autoimmune and infectious diseases. Recent association studies have found that the TNF-alpha-857T allele was associated with several disorders. Here we demonstrate, with reporter genes under the control of the two allelic TNF-alpha promoters, that the minor allele -857T is a much stronger transcriptional activator than the major allele -857C in RAW264.7 cell line in response to lipopolysaccharide stimulation. However, the result was not consistent in HeLa cell line. Furthermore, for the quantitative analysis of TNF-alpha synthesis between the -857C/C genotype from healthy subjects and the -857C/T genotype from AS patients, the quantitative reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay were performed separately. There was no significant difference between the two groups at the level of mRNA and protein. These results show that this polymorphism may have a direct effect on TNF-alpha regulation in a tissue-specific manner, and apart from the polymorphism at -857 in the TNF-alpha promoter, there may be other factors affecting the expression of TNF-alpha.

Adult↗
PubMed2005

The HNPCC associated MSH2*1906G-->C founder mutation probably originated between 1440 CE and 1715 CE in the Ashkenazi Jewish population.

The MSH2*1906G-->C mutation was recently shown to be a rare yet highly penetrant mutation leading to colorectal cancer. The mutation was only found among Ashkenazi Jewish individuals and lies on an extended haplotype that is common in that population. This study determined that the mutation probably arose between 11 and 22 generations ago, during the time when the Ashkenazim were living in eastern Europe.

Alleles↗
PubMed2003

Construction of two BAC libraries from the wild Mexican diploid potato, Solanum pinnatisectum, and the identification of clones near the late blight and Colorado potato beetle resistance loci.

To facilitate isolation and characterization of disease and insect resistance genes important to potato, two bacterial artificial chromosome (BAC) libraries were constructed from genomic DNA of the Mexican wild diploid species, Solanum pinnatisectum, which carries high levels of resistance to the most important potato pathogen and pest, the late blight and the Colorado potato beetle (CPB). One of the libraries was constructed from the DNA, partially digested with BamHI, and it consists of 40328 clones with an average insert size of 125 kb. The other library was constructed from the DNA partially digested with EcoRI, and it consists of 17280 clones with an average insert size of 135 kb. The two libraries, together, represent approximately six equivalents of the wild potato haploid genome. Both libraries were evaluated for contamination with organellar DNA sequences and were shown to have a very low percentage (0.65-0.91%) of clones derived from the chloroplast genome. High-density filters, prepared from the two libraries, were screened with ten restriction fragment length polymorphism (RFLP) markers linked to the resistance genes for late blight, CPB, Verticillium wilt and potato cyst nematodes, and the gene Sr1 for the self-incompatibility S-locus. Thirty nine positive clones were identified and at least two positive BAC clones were detected for each RFLP marker. Four markers that are linked to the late blight resistance gene Rpi1 hybridized to 14 BAC clones. Fifteen BAC clones were shown to harbor the PPO (polyphenol oxidase) locus for the CPB resistance by three RFLP probes. Two RFLP markers detected five BAC clones that were linked to the Sr1 gene for self-incompatibility. These results agree with the library's predicted extent of coverage of the potato genome, and indicated that the libraries are useful resources for the molecular isolation of disease and insect resistance genes, as well as other economically important genes in the wild potato species. The development of the two potato BAC libraries provides a starting point, and landmarks for BAC contig construction and chromosome walking towards the map-based cloning of agronomically important target genes in the species.

Animals↗
PubMed2003

Age-related thymic involution in C57BL/6J x DBA/2J recombinant-inbred mice maps to mouse chromosomes 9 and 10.

A comprehensive analysis of initial thymus size and involution rate has not been quantitated for different genetic backgrounds of mice, thus genetic linkage analysis of thymic involution has not been possible. Here, we have used a mathematical method to analyze the age-related decline in thymocyte count in C57BL/6 and DBA/2 mice and have observed that thymic involution could be best fit with a negative exponential curve N(t)=beta(0) x exp(-beta(1)t), where t represents the age (day). This regression model was applied to C57BL/6 x DBA/2 (B x D) recombinant inbred strains of mice to identify the genetic loci influencing age-related thymic involution. There was a dramatic genetic effect of B and D alleles on thymocyte count at young age and the age-related thymic involution rate. The strongest quantitative trait loci (QTL) influencing the rate of thymic involution were mapped to mouse chromosome (Chr) 9 (D9Mit20 at 62 cM) and Chr 10 (D10Mit61 at 32 cM). The strongest QTLs influencing the initial thymocyte count were mapped to ChrX (DXMit324 at 26.5 cM) and Chr 3 (D3Mit127 at 70.3 cM). The present study suggests that the initial thymus size and the rate of thymic involution may be influenced by a relatively small number of genetic loci.

Aging↗
PubMed2002

Use of endoscopic ultrasound-guided injection in endoscopic resection of solid submucosal tumors.

AIMS: Submucosal tumor (SMT) is a common disease. We used endoscopic ultrasound (EUS)-guided puncture to inject saline before resection of SMTs, and evaluated the usefulness of this method. PATIENTS AND METHODS: We selected 16 symptomatic patients with solid SMTs in the upper gastrointestinal tract, confirmed by endoscopy and EUS. We first used EUS-guided puncture to inject saline to separate the submucosal lesions from the deeper normal tissues. Lesions in the muscularis mucosa and submucosa were then removed directly by snare cauterization. Lesions in the muscularis propria were treated by means of a two-step approach: first, we incised the superficial tissue of the tumors using an electrosurgical needle, and second, we enucleated SMTs as much as possible by tightening the snare around them and creating pseudo-stalks. After snare excision of SMTs, the cleavages of the superficial tissues were closed using metal clips. RESULTS: Among the 16 patients, one lesion was in the muscularis mucosa, six were in the submucosa, and nine were in muscularis propria. All the lesions were resected thoroughly. No perforation occurred nor had any recurrences been observed at follow-up of 12 - 17 months. CONCLUSIONS: EUS-guided puncture to inject saline before resection is a safe and accurate procedure in the treatment of submucosal tumors.

Adult↗
PubMed2001

Substance P enhances HIV-1 replication in latently infected human immune cells.

Substance P (SP) is a potent modulator of neuroimmunoregulation. SP receptors are present on human monocytes and T lymphocytes, and SP alters the function of these immune cells. We investigated the effects of SP on HIV-1 replication in latently infected human immune cells. SP significantly enhanced HIV-1 replication in the latently infected promonocytic cell line (U1) and T lymphocyte line (ACH-2) stimulated with tumor necrosis factor (TNF-alpha). When added to these cells in combination with TNF-alpha, SP also enhanced HIV-1 gag gene expression in U1 and ACH-2 cells. This stimulatory effect of SP was associated with the activation of HIV-LTR (long terminal repeat) driven chloramphenicol acetyltransferase (CAT) gene expression, and could be blocked by pretreatment of U1 and ACH-2 cells with an SP receptor antagonist RP-67,580, indicating specific SP receptor-mediated regulation. Furthermore, the addition of SP to the cultures of latently infected peripheral blood mononuclear cells isolated from HIV-1-infected patients enhanced HIV-1 gag gene expression. Thus, SP may play a potentially important role as a positive regulator of HIV-1 replication in latently infected monocytes and lymphocytes. These observations may have significant implications toward understanding the role of neuropeptide SP in the immunopathogenesis of HIV-1 infection and AIDS.

Adult↗
PubMed2001

Apoptosis of airway epithelial cells induced by corticosteroids.

Damage to the airway epithelium is one prominent feature of chronic asthma. Corticosteroids induce apoptosis in inflammatory cells, which in part explains their ability to suppress airway inflammation. However, corticosteroid therapy does not necessarily reverse epithelial damage. We hypothesized that corticosteroids may induce airway epithelial cell apoptosis as one potential explanation for persistent damage. We tested this hypothesis in cultured primary central airway epithelial cells and in the cell line 1HAEo(-). Treatment with dexamethasone, beclomethasone, budesonide, or triamcinolone each elicited a time-dependent and concentration-dependent cell death. This cell death was associated with cleavage of nuclear chromatin, mitochondrial depolarization, cytochrome c extrusion, activation of caspase-9, and expression of phosphatidylserine on the outer cell membrane. Inhibitors of caspase activity blocked apoptotic cell death, as did overexpression of the apoptosis regulators Bcl-2 or Bcl-x(L). We demonstrated that CD95 ligation is not essential for the corticosteroid-induced apoptosis in airway epithelial cells. These data demonstrate that corticosteroids induce apoptotic cell death of airway epithelium. This raises the possibility that at least one of the major components of chronic airway damage in asthma, epithelial shedding and denudation, may in part result from a major therapy for the disease.

Anti-Asthmatic Agents↗
PubMed2001

Proinflammatory and regulatory cytokine production associated with innate and adaptive immune responses in children with autism spectrum disorders and developmental regression.

We determined innate and adaptive immune responses in children with developmental regression and autism spectrum disorders (ASD, N=71), developmentally normal siblings (N=23), and controls (N=17). With lipopolysaccharide (LPS), a stimulant for innate immunity, peripheral blood mononuclear cells (PBMCs) from 59/71 (83.1%) ASD patients produced >2 SD above the control mean (CM) values of TNF-alpha, IL-1beta, and/or IL-6 produced by control PBMCs. ASD PBMCs produced higher levels of proinflammatory/counter-regulatory cytokines without stimuli than controls. With stimulants of phytohemagglutinin (PHA), tetanus, IL-12p70, and IL-18, PBMCs from 47.9% to 60% of ASD patients produced >2 SD above the CM values of TNF-alpha depending on stimulants. Our results indicate excessive innate immune responses in a number of ASD children that may be most evident in TNF-alpha production.

Adaptation, Physiological↗
PubMed2001

A comparison of myocardial function after primary cardiac and primary asphyxial cardiac arrest.

Although myocardial dysfunction after resuscitation from ventricular fibrillation (VF) has been extensively investigated, less is known of the function of the myocardium after asphyxial cardiac arrest. The present experimental study was designed to compare postresuscitation left ventricular (LV) function after cardiac arrest caused by asphyxia with that of cardiac arrest induced by dysrhythmia. Four groups of Sprague-Dawley rats, which included eight animals in each group, were investigated. In the first two groups, cardiac arrest followed asphyxia produced by neuromuscular blockade with and without airway obstruction. In a third group, cardiac arrest was induced by electrical fibrillation of the ventricle. The fourth group represented animals in which the duration of asphyxial cardiac arrest was maintained for a time interval corresponding to that of the VF group. The fourth group received approximately the same number of electrical shocks as the third (VF) group. All animals were successfully resuscitated with precordial compression and mechanical ventilation. Postresuscitation measurements, including cardiac output, LV end-diastolic pressure (LVEDP), rate of pressure rise at LV pressure of 40 mm Hg (LV dP/dt40), and negative LV dP/dt, demonstrated decreased myocardial function in each group. No differences in cardiac function were observed between the animals with primary respiratory arrest whether or not the airway was obstructed. However, disproportionate and consistently greater impairment in myocardial function followed primary cardiac arrest due to VF when compared with equal duration of asphyxial cardiac arrest. We conclude that in this healthy animal model, asphyxial cardiac arrest resulted in significantly lesser impairment of postresuscitation myocardial function when compared with cardiac arrest caused by VF.

Animals↗
PubMed2001

Direct investigation of superparamagnetism in Co nanoparticle films.

A direct probe of superparamagnetism was used to determine the complete anisotropy energy distribution of Co nanoparticle films. The films were composed of self-assembled lattices of uniform Co nanoparticles of 3 or 5 nm in diameter, and a variable temperature scanning-SQUID microscope was used to measure temperature-induced spontaneous magnetic noise in the samples. Accurate measurements of anisotropy energy distributions of small volume samples will be critical to magnetic optimization of nanoparticle devices and media.

Journal Article↗
PubMed2001

Surface recognition of a protein using designed transition metal complexes.

Each protein has a unique pattern of histidine residues on the surface. This paper describes the design, synthesis, and binding studies of transition metal complexes to target the surface histidine pattern of carbonic anhydrase (bovine erythrocyte). When the pattern of cupric ions on a complex matches the surface pattern of histidines of the protein, strong and selective binding can be achieved in aqueous buffer (pH = 7.0). The described method of protein recognition is applicable to proteins of known structures. With rapidly increasing number of solved protein structures, the method has wide applicability in purification, targeting, and sensing of proteins.

Animals↗