Biomedical subjects

Li Li

Publications and source records attributed to Li Li.

At least 55 records · Page 3Linked to original sources

PubMed2006

Taeniasis/cysticercosis in a Tibetan population in Sichuan Province, China.

The results of a preliminary survey of taeniasis/cysticercosis in Yajiang County, Ganze Tibetan Prefecture in southwest Sichuan Province, China, indicated a very high prevalence of taeniasis (22.5%), with Taenia saginata as the dominant species. There was also a significant occurrence of late-onset epilepsy (8.5% prevalence and 16.4% seropositive for Taenia solium antibodies) attributable in large part to probable neurocysticercosis caused by T. solium. The poor sanitation and hygiene in this Tibetan community likely contributed to a high risk of human cysticercosis despite a low level of T. solium taeniasis (actually no T. solium carriers were detected amongst the 21 proven Taenia carriers). In addition, three taeniasis cases were confirmed by DNA genotyping as Taenia asiatica, which is the first report of this tapeworm in Tibetans, the first report for Sichuan Province and only the third report for mainland China.

Adolescent↗

PubMed2006

Growth promoting effect of a transgenic Bacillus mucilaginosus on tobacco planting.

In this study, we have investigated the plant growth promoting effect of Bacillus mucilaginosus strain D(4)B(1), a rhizosphere soil organism, and its transgenic strain NKTS-3 on tobacco planting. The transgenic strain contains a phytase expression cassette that can express high active phytase extracellularly and hydrolyze phytate in the soil to liberate inorganic phosphorus for the growth of tobacco plants. Greenhouse study and field experiments showed that both wild-type B. mucilaginosus and the transgenic strain could promote tobacco plant growth. Moreover, the transgenic strain promoted tobacco plant growth (235% more than control in pot experiments and 125% more than control in field experiments) was higher than the wild-type B. mucilaginosus (183% more than control in pot experiments and 108% more than control in field experiments). In addition, the inoculation with transgenic rhizobacteria could significantly improve root acquisition of phosphorus and increase the phosphorus content of the plant.

6-Phytase↗

PubMed2006

Distinct EBV and CMV reactivation patterns following antibody-based immunosuppressive regimens in patients with severe aplastic anemia.

The natural history of EBV and CMV reactivation and the potential for serious complications following antibody-based immunosuppressive treatment for bone marrow failure syndromes in the absence of transplantation is not known. We monitored blood for EBV and CMV reactivation by polymerase chain reaction (PCR) weekly in 78 consecutive patients (total of 99 immunosuppressive courses) with aplastic anemia. Four regimens were studied: (1) HC, horse ATG/cyclosporine; (2) HCS, horse ATG/CsA/sirolimus; (3) RC, rabbit ATG/CsA; and (4) CP, alemtuzumab. There were no cases of EBV or CMV disease, but EBV reactivation occurred in 82 (87%) of 94 and CMV reactivation in 19 (33%) of 57 seropositive patients after starting immunosuppression. The median peak EBV copies were higher in the RC group when compared with HC, HCS, and alemtuzumab (P < .001). The median duration of PCR positivity for EBV was higher in the RC group compared with HC, HCS, and alemtuzumab (P = .001). Subclinical reactivation of both EBV and CMV is common and nearly always self-limited in patients with bone marrow failure receiving immunosuppression; different regimens are associated with different intensity of immunosuppression as measured by viral load and lymphocyte count; and viral reactivation patterns differ according to immunosuppressive regimens.

Adolescent↗

PubMed2006

Germline gain-of-function mutations in SOS1 cause Noonan syndrome.

Noonan syndrome, the most common single-gene cause of congenital heart disease, is characterized by short stature, characteristic facies, learning problems and leukemia predisposition. Gain-of-function mutations in PTPN11, encoding the tyrosine phosphatase SHP2, cause approximately 50% of Noonan syndrome cases. SHP2 is required for RAS-ERK MAP kinase (MAPK) cascade activation, and Noonan syndrome mutants enhance ERK activation ex vivo and in mice. KRAS mutations account for <5% of cases of Noonan syndrome, but the gene(s) responsible for the remainder are unknown. We identified missense mutations in SOS1, which encodes an essential RAS guanine nucleotide-exchange factor (RAS-GEF), in approximately 20% of cases of Noonan syndrome without PTPN11 mutation. The prevalence of specific cardiac defects differs in SOS1 mutation-associated Noonan syndrome. Noonan syndrome-associated SOS1 mutations are hypermorphs encoding products that enhance RAS and ERK activation. Our results identify SOS1 mutants as a major cause of Noonan syndrome, representing the first example of activating GEF mutations associated with human disease and providing new insights into RAS-GEF regulation.

Adolescent↗

PubMed2006

Adventitial fibroblasts are activated in the early stages of atherosclerosis in the apolipoprotein E knockout mouse.

The role of the adventitia in vascular function and vascular lesion formation has been largely ignored. This study observed the activation of the adventitia and specifically the fibroblasts in the development of atherosclerosis in the apoE(-/-) mouse. The results showed a gradual increase in expression of collagen types I and III after 2, 4, and 8 weeks of hyperlipidic diet. The earliest expression of monocyte chemoattractant protein-1 (MCP-1) protein and mRNA was detected in the adventitial fibroblast before the formation of intimal lesions. Proliferation, too, was first found in the adventitial fibroblasts. We hypothesize that the adventitial fibroblast is activated in the early stage of atherosclerosis. Adventitial inflammation may be an early event in the development of atherosclerotic lesions.

Animals↗

PubMed2006

Designer genes: Filling the gap in transplantation.

Accelerated evolution of the field of functional genomics has been greatly facilitated by high-throughput microarray-based gene function studies, relating to the parallel and serial expression measurements of genomes. Microarray experimentation is being applied for the study of basic research questions, drug target discovery, pharmacology, toxicogenomics, target selectivity, disease biomarker determination, development of prognostic tests, and disease subclass determination. This article will review the current applications of microarray technology in the field of organ transplantation and discuss the potential impact of this technology on transplantation medicine.

Genetic Engineering↗

PubMed2006

Nearly identical paralogs: implications for maize (Zea mays L.) genome evolution.

As an ancient segmental tetraploid, the maize (Zea mays L.) genome contains large numbers of paralogs that are expected to have diverged by a minimum of 10% over time. Nearly identical paralogs (NIPs) are defined as paralogous genes that exhibit > or = 98% identity. Sequence analyses of the "gene space" of the maize inbred line B73 genome, coupled with wet lab validation, have revealed that, conservatively, at least approximately 1% of maize genes have a NIP, a rate substantially higher than that in Arabidopsis. In most instances, both members of maize NIP pairs are expressed and are therefore at least potentially functional. Of evolutionary significance, members of many NIP families also exhibit differential expression. The finding that some families of maize NIPs are closely linked genetically while others are genetically unlinked is consistent with multiple modes of origin. NIPs provide a mechanism for the maize genome to circumvent the inherent limitation that diploid genomes can carry at most two "alleles" per "locus." As such, NIPs may have played important roles during the evolution and domestication of maize and may contribute to the success of long-term selection experiments in this important crop species.

Arabidopsis↗

PubMed2006

Adiponectin modulates carnitine palmitoyltransferase-1 through AMPK signaling cascade in rat cardiomyocytes.

Adiponectin, an adipocyte-derived polypeptide hormone, plays an important role in regulating fatty acid oxidation. beta-oxidation of fatty acids supplies most of the cardiac energy and carnitine palmitoyltransferase (CPT)-1 serves as a key regulator during this process. To characterize the potential effects of adiponectin on CPT-1, we incubated rat neonatal cardiomyocytes with globular adiponectin (gAd). Results showed that gAd promoted the activity and mRNA expression of CPT-1. The underlying signal pathway involved in this modulatory effect was further investigated. Inhibition of AMP-activated protein kinase (AMPK) with adenine 9-beta-d-arabinofuranoside (AraA) completely abrogated gAd-mediated AMPK and acetyl coenzyme A carboxylase (ACC) phosphorylation and suppressed the promotion of CPT-1 activity. gAd also induced the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and peroxisome proliferator-activated receptor (PPAR)-alpha, which was inhibited by AraA. SB202190, a p38MAPK inhibitor, blocked gAd-stimulated PPAR-alpha phosphorylation. When AMPK and/or p38MAPK was inhibited, gAd-enhanced mRNA expression of CPT-1 was partially reduced. In conclusion, our study suggests that the activation of AMPK signaling cascade participates in the promotion effect of gAd on CPT-1.

AMP-Activated Protein Kinases↗

PubMed2006

Gene discovery and annotation using LCM-454 transcriptome sequencing.

454 DNA sequencing technology achieves significant throughput relative to traditional approaches. More than 261,000 ESTs were generated by 454 Life Sciences from cDNA isolated using laser capture microdissection (LCM) from the developmentally important shoot apical meristem (SAM) of maize (Zea mays L.). This single sequencing run annotated >25,000 maize genomic sequences and also captured approximately 400 expressed transcripts for which homologous sequences have not yet been identified in other species. Approximately 70% of the ESTs generated in this study had not been captured during a previous EST project conducted using a cDNA library constructed from hand-dissected apex tissue that is highly enriched for SAMs. In addition, at least 30% of the 454-ESTs do not align to any of the approximately 648,000 extant maize ESTs using conservative alignment criteria. These results indicate that the combination of LCM and the deep sequencing possible with 454 technology enriches for SAM transcripts not present in current EST collections. RT-PCR was used to validate the expression of 27 genes whose expression had been detected in the SAM via LCM-454 technology, but that lacked orthologs in GenBank. Significantly, transcripts from approximately 74% (20/27) of these validated SAM-expressed "orphans" were not detected in meristem-rich immature ears. We conclude that the coupling of LCM and 454 sequencing technologies facilitates the discovery of rare, possibly cell-type-specific transcripts.

Base Sequence↗

PubMed2006

Magnetic resonance imaging of retropharyngeal lymph node metastasis in nasopharyngeal carcinoma: patterns of spread.

PURPOSE: To investigate the incidence, distribution, and spread pattern of retropharyngeal lymph node (RLN) involvement in patients with nasopharyngeal carcinoma (NPC) by using magnetic resonance imaging (MRI). METHODS AND MATERIALS: The MR images of 275 patients with newly diagnosed NPC were reviewed retrospectively. Nodes were classified as metastatic based on size criteria, the presence of nodal necrosis, and extracapsular spread. RESULTS: Retropharyngeal lymph node involvement was detected in 175 (63.6%) patients. Metastatic RLNs were seen at the following levels: occipital bone, 24 (9.6%) nodes; C1, 157 (62.5%) nodes; C1/2, 40 (15.9%) nodes; C2, 27 (10.8%) nodes; C2/3, 1 (0.4%) node; and C3, 2 (0.8%) nodes. The incidence of RLN involvement was equal to the incidence of cervical lymph node involvement (81.4% vs. 81.4%) in 215 patients with nodal metastases. A significantly higher incidence of metastatic RLNs was observed in the presence of oropharynx, prestyloid parapharyngeal space, post-styloid parapharyngeal space, longus colli muscle, medial pterygoid muscle, levator muscle of velum palatini, tensor muscle of velum palatini, Level II node, Level III node, and Level V node involvement. A significantly lower incidence of metastatic RLNs was found in T1, N0, and Stage I disease. Conversely, no significant difference in the incidence of metastatic RLNs was observed between T1, 2, and, 3; N2 and N3; or Stage II, III, and IV disease. CONCLUSIONS: There is an orderly decrease in the incidence of metastatic lateral RLNs from the C1 to C3 level. Metastatic RLNs associate well with involvement of certain structures in early stage primary tumors and lymph node metastases of the upper jugular chain (Level II, Level III nodes) and the posterior triangle (Level V nodes). Both RLNs and cervical Level II nodes appear to be the first-echelon nodes in NPC.

Adult↗

PubMed2006

Keggin POM microtubes: a coincident product of crystal growth and species transformation.

Microtubes of alpha-K4SiW12O40 with the length around 1 cm and inner diameter and wall thickness in the ranges of 7-55 mum and 3-15 mum, respectively, were copiously fabricated by a one-step, template-free aqueous synthesis. The formation mechanism is discussed. The discovered tubular structure of the polyoxometalate is believed to be promising for use in templates, as a precursor of tungsten oxide ceramic microtubes, and for other uses associated with tubular structures.

Journal Article↗

PubMed2006

[Effects of chloride channel blockers on excitatory junction potentials in smooth muscle cells of cochlear spiral modiolar artery in guinea pigs].

Chloride channels have been identified in vascular smooth muscle cells (SMCs). It has been shown that these channels are involved in myogenic tone regulation and neuromuscular transmission in various vascular beds. However, whether the chloride channels are responsible for the formation of excitatory junction potentials (EJPs) of SMCs in the spiral modiolar artery (SMA) remains unelucidated. In the present study, the effects of chloride channel blockers (niflumic acid, NFA; indanyloxyacetic acid 94, IAA-94; disodium 4, 4'-diisothiocyanatostilbene-2, 2'-disulfonate, DIDS) on EJP were explored in guinea pigs, using intracellular recording techniques on acutely isolated SMA. It was found that EJP was evoked in the majority of the SMCs (75%, n=49) with an adequate electronic stimulation. The amplitude of the EJP was partially blocked (30% approximately 80%) by combined application of alpha(1) receptor antagonist (prazosin) and alpha(2) receptor antagonist (idazoxan) at concentration of up to 1 micromol/L, and P(2x) receptor antagonist (PPADS, 10 approximately 100 micromol/L). NFA (100 micromol/L) could further inhibit the residual EJP in the presence of alpha(1), alpha(2)-adrenergic and P(2x) receptor antagonists. IAA-94 or DIDS not only inhibited the amplitude but also shortened the duration of EJP. Decrease of extracellular chloride concentration from 135.6 mmol/L to 60 mmol/L would enhance EJP. Moreover, IAA-94 (100 micromol/L) and DIDS (200 mumol/L) could reverse the enhancement of EJP by low extracellular Cl(-). NFA (100 micromol/L) could also block the residual depolarizations evoked by norepinephrine (NE, 1 approximately 50 micromol/L). Based on these results, it is inferred that NE could activate a novel adrenoceptor to open the chloride channel on the membrane of the SMCs, leading to a transmembrane Cl(-) current. This current is involved, at least partially, in the formation of EJP.

Adrenergic alpha-Antagonists↗

PubMed2006

Immunological evaluation of SW-HSA conjugate on goats.

Locoweeds cause significant livestock poisoning and economic loss all over the world. The purpose of this study was to investigate the immune effects of locoweed toxin, swainsonine (SW) and human serum albumin (HSA) conjugate (SW-HSA), on goats. Twenty-four Sannon goats were randomly separated into immune control group (eight goats), immune poisoning group I (six goats), immune poisoning group II (six goats) and poisoning control group (four goats). Immune control group, immune poisoning groups I and II were first vaccinated with SW-HSA conjugate. The poisoning control group, immune poisoning groups I and II were then fed with 10.0 g/kg BW/day dry powder of Oxytropis kansuensis Bunge everyday morning. The immune control group was supplied with an alfalfa-based diet. Blood samples of these experimental animals were collected at different time interval. Immunoassay was performed using indirect ELISA and E-rosette technique. The results show that, after second booster immunization: (1) anti-SW antibody level in some goats increased to 2(8), which proves that SW-HSA conjugate can induce experimental animals to produce high-level anti-SW antibody in their bodies; (2) the high-level antibody in their bodies could maintain 30 days, and decreased gradually after poisoning experiment (in our experiment, there was a return of the antibody level on day 21 after poisoning experiment); (3) the decreasing of the E-rosette rate of the immune poisoning group was delayed 14 days, which suggests that SW-HSA could low down the loss of the immunity of the goats; (4) swainsonine concentration in the blood was significantly lower (p<0.01) in the immune poisoning groups than that in the poisoning control group, and there was no significant difference (p>0.01) between the two immune poisoning groups within the poisoning experiment.

Animals↗

PubMed2006

Polyphenolic profiles and antioxidant activities of heartnut (Juglans ailanthifolia Var. cordiformis) and Persian walnut (Juglans regia L.).

The polyphenolic compositions of three heartnut (Juglans ailanthifolia var. cordiformis) varieties (Imshu, Campbell CW1, and Campbell CW3) were examined and compared with those of two Persian walnut (Juglans regia L.) varieties (Combe and Lake). The nuts were defatted, extracted, and separated into three different fractions, the free phenolic acid (FPA), acid-hydrolyzable phenolic acid (AHPA), and bound phenolic acid (BPA) fractions. The total phenolic contents (TPCs) in both FPA and AHPA of the Persian walnuts were significantly higher (P < 0.001) than those of the heartnuts, but not in the BPA (P = 0.20). LC-ESI-MS(n)() studies revealed that except for the FPA fraction, the major polyphenolics in both heartnut and Persian walnut were ellagic acid and valoneic acid dilactone. Persian walnuts contained an average of 0.29 and 1.31 mg of ellagic acid/g nut in the 80% methanol extractable fractions FPA and AHPA, respectively. Heartnuts contained an average of 0.16 and 0.60 mg of ellagic acid/g nut in the respective fractions. Bound ellagic acid in the residue was 0.93 and 0.70 mg/g of nut in the Persian walnut and in the heartnut, respectively. Valoneic acid dilactone was tentatively identified and quantified as milligrams of ellagic acid equivalent per gram of nut. These components were found to contribute to the strong total antioxidant activities measured using ferric reducing antioxidant power and photochemiluminescence methods.

Antioxidants↗

PubMed2006

A genetic linkage map of Pacific white shrimp (Litopenaeus vannamei): sex-linked microsatellite markers and high recombination rates.

Pacific white shrimp (Litopenaeus vannamei) is the leading species farmed in the Western Hemisphere and an economically important aquaculture species in China. In this project, a genetic linkage map was constructed using amplified fragment length polymorphism (AFLP) and microsatellite markers. One hundred and eight select AFLP primer combinations and 30 polymorphic microsatellite markers produced 2071 markers that were polymorphic in either of the parents and segregated in the progeny. Of these segregating markers, 319 were mapped to 45 linkage groups of the female framework map, covering a total of 4134.4 cM; and 267 markers were assigned to 45 linkage groups of the male map, covering a total of 3220.9 cM. High recombination rates were found in both parental maps. A sex-linked microsatellite marker was mapped on the female map with 6.6 cM to sex and a LOD of 17.8, two other microsatellite markers were also linked with both 8.6 cM to sex and LOD score of 14.3 and 16.4. The genetic maps presented here will serve as a basis for the construction of a high-resolution genetic map, quantitative trait loci (QTLs) detection, marker-assisted selection (MAS) and comparative genome mapping.

Animals↗

PubMed2006

Different signaling responses to anti-proliferative agents in human aortic and venous smooth muscle cells.

Proliferation of smooth muscle cells (SMCs) contributes to the stenosis of coronary arteries and vascular grafts. Local delivery of anti-proliferative drugs can prevent vascular stenosis. To understand the cellular responses to anti-proliferative agents, we investigated the signaling events in cultured human aortic SMCs (ASMCs), saphenous venous SMCs (VSMCs), and dermal fibroblasts (DFs) in response to paclitaxel or etoposide. Cellular mitochondrial and proliferative activities were examined with the methylthiazoletetrazolium (MTT) dye reduction and the bromodeoxyuridine (BrdU) incorporation assay, respectively. Cell proliferation was almost completely suppressed by paclitaxel or etoposide, but apoptosis was achieved in only about 50% of cells at the highest drug concentrations, suggesting the presence of compensatory mechanisms to prevent apoptosis. Examination of three important signaling pathways revealed significant differences between ASMCs, VSMCs, and DFs. Treatment with either paclitaxel or etoposide caused a transient phosphorylation/activation of p42 MAPK in ASMCs and DFs, but had no effect on phospho-p42/44 MAPK in VSMCs. High-dose etoposide enhanced p38 MAPK activation in ASMCs, but not in VSMCs. The p38 inhibitor, PD169316, partially inhibited etoposide-induced ASMC apoptosis, but induced apoptosis in VSMCs. The effects of etoposide and paclitaxel on Akt also differed between ASMCs and VSMCs. These observations indicate that ASMCs and VSMCs differ in the response of signaling pathways to anti-proliferative agents. In ASMCs, p42/44 MAPK appears to serve a pro-survival role, whereas p38 MAPK is a pro-apoptotic regulator. In contrast, p38 MAPK is an important pro-survival regulator in VSMCs and p42/44 MAPK appears to play a minor role in responding to anti-proliferative drugs.

Animals↗

PubMed2006

[Relationship between human age and mtDNA 4977 deletions in human blood cells].

OBJECTIVE: To study the relationship between human age and mtDNA 4977 deletions in human blood cells. METHODS: According to Anderson's sequence, two sets of primers were designed. Human mtDNA 4977 deletions in blood samples from 110 healthy human individuals in different age groups were examined by using Real time quantitative PCR. RESULTS: The mtDNA 4977 deletions could be observed unless the age was under 23 years old. The older the people were, the easier the deletion could be observed. CONCLUSION: mtDNA 4977 deletions in human blood cells were correlated with human ages in some extent.

Adolescent↗

PubMed2006

Genomic analysis reveals that Pseudomonas aeruginosa virulence is combinatorial.

BACKGROUND: Pseudomonas aeruginosa is a ubiquitous environmental bacterium and an important opportunistic human pathogen. Generally, the acquisition of genes in the form of pathogenicity islands distinguishes pathogenic isolates from nonpathogens. We therefore sequenced a highly virulent strain of P. aeruginosa, PA14, and compared it with a previously sequenced (and less pathogenic) strain, PAO1, to identify novel virulence genes. RESULTS: The PA14 and PAO1 genomes are remarkably similar, although PA14 has a slightly larger genome (6.5 megabses [Mb]) than does PAO1 (6.3 Mb). We identified 58 PA14 gene clusters that are absent in PAO1 to determine which of these genes, if any, contribute to its enhanced virulence in a Caenorhabditis elegans pathogenicity model. First, we tested 18 additional diverse strains in the C. elegans model and observed a wide range of pathogenic potential; however, genotyping these strains using a custom microarray showed that the presence of PA14 genes that are absent in PAO1 did not correlate with the virulence of these strains. Second, we utilized a full-genome nonredundant mutant library of PA14 to identify five genes (absent in PAO1) required for C. elegans killing. Surprisingly, although these five genes are present in many other P. aeruginosa strains, they do not correlate with virulence in C. elegans. CONCLUSION: Genes required for pathogenicity in one strain of P. aeruginosa are neither required for nor predictive of virulence in other strains. We therefore propose that virulence in this organism is both multifactorial and combinatorial, the result of a pool of pathogenicity-related genes that interact in various combinations in different genetic backgrounds.

Base Sequence↗