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Biomedical subjects

Jun Liu

Publications and source records attributed to Jun Liu.

At least 127 records · Page 7Linked to original sources
PubMed2006

[Correlation analysis on the malocclusion and articulation of skeletal angle III malocclusion in mixed dentition].

OBJECTIVE: To investigate the effects of skeletal Class III malocclusion in mixed dentition on speech articulation and to look for which factors lead to the speech errors. METHODS: Thirty-eight children with skeletal Angle Ill malocclusion in mixed dentition were selected as a sample group and 40 children with normal occlusion in mixed dentition as a control group. Two phoneticians evaluated their articulations and wrote down error phonemes respectively. The correlation analysis was undertaken between the number of errors and the measurements of patients' cephalometry. RESULTS: The number of errors were correlated significantly with overbite, UI-LI, OBJ (OB+OJ) and TD-PW. CONCLUSION: There is articulatory malfunction in the majority of skeletal Angle III malocclusion patients in mixed dentition. Articulatory malfunction is related to the position of incisors and the tongue.

Cephalometry↗
PubMed2006

[Repairing widespread traumatic soft tissue defects in lower limb with free latissimus dorsi muscle-skin flaps].

OBJECTIVE: To explore the results of repairing widespread traumatic soft tissue defects in the heels and adjacent regions with free latissimus dorsi muscle-skin flaps. METHODS: From March 1998 to May 2005, 10 cases of widespread traumatic soft tissue defects in the heels and adjacent regions were repaired with free latissimus dorsi muscle-skin flaps; Of the 10 patients, 9 were male and 1 was female, whose ages ranged from 32 to 60 years, and the disease course was 2 hours to 2 months. The defect was by plough-machine injury in 5 cases, by crush injury in 2 cases, by snake injury in 2 cases, and electricity injury in 1 case. Eight cases of defects involved in the posterior of heel and leg, the defect area ranged from 21 cm x 12 cm to 35 cm x 15 cm; 2 cases had widespread soft tissue defects on heel, ankle, sole and dorsal foot, and the defect area was 27 cmX 14 cm and 30 cm x 21 cm respectively. All cases were accompanied by the exposure of bone; 6 cases by fracture; 4 cases by open infection of ankle joint; and 2 cases by injuries of the posterior tibial vessel and the tibial nerve. The sizes of the dissected flap ranged from 25 cm x 14 cm to 33 cm x 24 cm. The donor sites were covered by large mid-thickness flap. RESULTS: There were no postoperative complication of vascular crisis and infection. Ten flaps survived completely and the wounds healed by first intention. After a follow-up of 3 to 24 months, five cases received two-stage plastic operation because bulky flaps bring some trouble in wearing shoes. In 5 cases of reconstructed sensation, two cases recovered pain and temperature sensation. All cases recovered the abilities to stand and walk without ulcer complication. CONCLUSION: The free latissimus dorsi muscle-skin flap is an ideal flap for repairing widespread traumatic soft tissue defects and infectious wounds with muscle defects and bone exposure in the heel and adjacent regions, because it has such advantages as adequate blood supply, big dermatomic area, and excellent ability to resist infection.

Adult↗
PubMed2005

Response of porcine hepatocytes in primary culture to plasma from severe viral hepatitis patients.

AIM: To observe the effects of plasma from patients with severe viral hepatitis (SVHP) on the growth and metabolism of porcine hepatocytes and the clinical efficiency of bioartificial liver device. METHODS: Hepatocytes were isolated from male porcines by collagenase perfusion. The synthesis of DNA and total protein, leakages of AST and LDH, changes in glutathione (GSH), catalase and morphology of porcine hepatocytes exposed to SVHP were investigated to indicate the effect of plasma from patients with severe hepatitis on the growth, injury, detoxification, and morphology of porcine hepatocytes. RESULTS: The synthesis of DNA and protein was inhibited in the medium containing 100% SVHP compared to the controls. The leakages of LDH and AST increased in porcine hepatocytes following exposure to 100% SVHP for 5 h. The difference between 100% SVHP and 10% newborn calf serum (NCS) was significant in t-test (LDH: t = 24.552, P = 0.001; AST: t = 4.169, P = 0.014). After exposure to SVHP for 24 h, alterations in GSH status were significant (F = 2.746, P<0.05) between porcine hepatocytes in 100% SVHP and 10% NCS, but no alteration occurred in the culture medium after 48 h (F = 4.378, P<0.05). A similar profile was observed in catalase activity. Many round vacuoles were observed in porcine hepatocytes cultured in SVHP. The membranes of these cells became indistinct and almost all the cells died on d 5. CONCLUSION: Plasma from patients with severe hepatitis inhibits the growth, injures membrane, disturbs GSH homeostasis and induces morphological changes of porcine hepatocytes. It is suggested that SVHP should be pretreated to reduce the toxin load and improve the performance of porcine hepatocytes in extracorporeal liver-support devices.

Animals↗
PubMed2005

Gray matter density reduction in the insula in fire survivors with posttraumatic stress disorder: a voxel-based morphometric study.

Voxel-based morphometry (VBM) is an objective whole-brain technique for characterizing regional cerebral volume and tissue concentration differences in structural magnetic resonance images. In the current study, we used VBM to examine possible cerebral gray matter abnormalities in patients with posttraumatic stress disorder (PTSD) due to fire. The subjects included 12 victims of a fire disaster with PTSD and 12 matched victims of the same fire without PTSD. Magnetic resonance images were obtained on a 1.5-Tesla General Electric scanner at Central South University, and an entire brain volume of 248 contiguous slices was obtained for each subject. Then, gray matter density in patients with PTSD and control groups was compared by using a VBM approach in SPM2. Group analysis was thresholded at P<0.001, uncorrected, at the voxel level. The following three regions of reduced gray matter volume were found in patients with PTSD compared with controls: left hippocampus, left anterior cingulate cortex (ACC), and bilateral insular cortex. It was concluded that there are structural abnormalities of the hippocampus, the ACC and the insular cortex in patients with PTSD due to fire.

Adult↗
PubMed2005

Inhibition of aluminum oxyhydroxide precipitation with citric acid.

Citric acid has been shown to act as an agent for increasing the solubility of aluminum oxyhydroxides in aqueous solutions of high (>2.47 mol/mol) hydroxide-to-aluminum ratios. Conversely, citric acid also colloidally stabilizes particles in aqueous suspensions of aluminum-containing particles. Solutions of aluminum chloride, with and without citric acid added, were titrated with NaOH(aq). The presence and size of particles were determined using quasi-elastic light scattering. In solutions that contained no citric acid, particles formed instantaneously when NaOH(aq) was added but these were observed to rapidly diminish in size, disappearing at OH/Al ratios below 2.5 mol/mol. When the OH/Al ratio was raised beyond 2.5 by adding more NaOH(aq), suspensions of colloidally stable particles formed. Large polycations containing 13 aluminum atoms were detected by (27)Al solution NMR in citric-acid-free solutions with OH/Al ratios slightly lower than 2.5. In comparison, adding citric acid to solutions of aluminum chloride inhibited the formation of large aluminum-containing polycations. The absence of the polycations prevents or retards the subsequent formation of particles, indicating that the polycations, when present, act as seeds to the formation of new particles. Particles did not form in solutions with a citric acid/aluminum ratio of 0.8 until sufficient NaOH(aq) was added to raise the OH/Al ratio to 3.29. By comparison, lower amounts of citric acid did not prevent particles from forming but did retard the rate of growth.

Journal Article↗
PubMed2005

ROR1/RPA2A, a putative replication protein A2, functions in epigenetic gene silencing and in regulation of meristem development in Arabidopsis.

We screened for suppressors of repressor of silencing1 (ros1) using the silenced 35S promoter-neomycin phosphotransferase II (Pro(35S):NPTII) gene as a marker and identified two allelic mutants, ror1-1 and ror1-2 (for suppressor of ros1). Map-based cloning revealed that ROR1 encodes a 31-kD protein similar to DNA replication protein A2 (RPA2A). Mutations in ROR1 reactivate the silenced Pro(35S):NPTII gene but not RD29A promoter-luciferase in the ros1 mutant. DNA methylation in rDNA, centromeric DNA, and RD29A promoter regions is not affected by ror1. However, chromatin immunoprecipitation data suggest that histone H3 acetylation is increased and histone H3K9 dimethylation is decreased in the 35S promoter in the ror1 ros1 mutant compared with ros1. These results indicate that release of silenced Pro(35S):NPTII by ror1 mutations is independent of DNA methylation. ROR1/RPA2A is strongly expressed in shoot and root meristems. Mutations in ROR1/RPA2A affect cell division in meristems but not final cell sizes. Our work suggests important roles of ROR1/RPA2A in epigenetic gene silencing and in the regulation of plant development.

Amino Acid Sequence↗
PubMed2005

Mucormycosis spondylodiscitis after lumbar disc puncture.

Vertebral osteomyelitis due to mucormycosis is a rare but fulminant and fatal disease. Only one case has been reported in literature, with postmortem diagnosis. The present paper reports a female case of mucormycosis spondylodiscitis and vertebral osteomyelitis after lumbar disc puncture and radio frequency nucleoplasty. She subsequently underwent two surgical debridements, continuous local irrigation and drainage, together with local and systemic Amphotericin B treatments. The infection was controlled 4 months after the second debridement; however, there was no improvement in the neurological function at the most recent follow-up, 16 months after the surgery. The experience of this patient, though a single case, supports early recognition, surgical debridement, systemic and local antifungal treatment, closed irrigation and drainage as the keys to successful treatment.

Antifungal Agents↗
PubMed2005

Pentacyclic triterpenes. Part 1: the first examples of naturally occurring pentacyclic triterpenes as a new class of inhibitors of glycogen phosphorylases.

The semi-synthesis, in vitro and in vivo biological evaluation of corosolic acid (1) and maslinic acid (2) are described. Compounds 1 and 2 represent a new class of inhibitors of glycogen phosphorylases. Both 1 and 2 inhibit the increase of fasted plasma glucose of diabetic mice induced by adrenaline. It is therefore proposed that naturally occurring pentacyclic triterpenes 1 and 2 might reduce blood glucose, at least in part, through inhibiting hepatic glycogen degradation.

Animals↗
PubMed2005

Age-related changes of nuclear architecture in Caenorhabditis elegans.

Mutations in lamins cause premature aging syndromes in humans, including the Hutchinson-Gilford Progeria Syndrome (HGPS) and Atypical Werner Syndrome. It has been shown that HGPS cells in culture undergo age-dependent progressive changes in nuclear architecture. However, it is unknown whether similar changes in nuclear architecture occur during the normal aging process. We have observed that major changes of nuclear architecture accompany Caenorhabditis elegans aging. We found that the nuclear architecture in most nonneuronal cell types undergoes progressive and stochastic age-dependent alterations, such as changes of nuclear shape and loss of peripheral heterochromatin. Furthermore, we show that the rate of these alterations is influenced by the insulin/IGF-1 like signaling pathway and that reducing the level of lamin and lamin-associated LEM domain proteins leads to shortening of lifespan. Our work not only provides evidence for changes of nuclear architecture during the normal aging process of a multicellular organism, but also suggests that HGPS is likely a result of acceleration of the normal aging process. Because the nucleus is vital for many cellular functions, our studies raise the possibility that the nucleus is a prominent focal point for regulating aging.

Aging↗
PubMed2005

LosA, a key glycosyltransferase involved in the biosynthesis of a novel family of glycosylated acyltrehalose lipooligosaccharides from Mycobacterium marinum.

Members of the genus Mycobacterium are characterized by cell envelopes rich in unusual free lipids, interacting with a covalently anchored mycolyl-arabinogalactan matrix. Previous studies have shown that Mycobacterium marinum produces large amounts of a diacylglycosylphenolphthiocerol, "phenolic" glycolipid. When cultivated on liquid Sauton medium, traces of a polar lipooligosaccharide (LOS) glycolipid antigen were also previously indicated. In this study, it was found that growth of the type strain of M. marinum on solid Sauton or Middlebrook 7H10 agar gave substantial, but different, amounts of a family of four major trehalose-based LOSs. The core pentasaccharide LOS-I was a rhamnosyl diglucosyl-acylated trehalose. The heptasaccharide, LOS-II, was derived from LOS-I by adding xylose accompanied by a novel sugar (X); repeated addition of this sugar unit X gave the octasaccharide LOS-III. LOS-IV has a decasaccharide component with two additional unusual sugar units, YZ. In a recent study (Alexander, D. C., Jones, J. R., Tan, T., Chen, J. M., and Liu, J. (2004) J. Biol. Chem. 279, 18824-18833), chromatographically similar glycolipids were assigned to the family of phosphatidylinositol mannosides (PIMs) and a "PimF" (Rv1500) glycosyltransferase implicated in the conversion of a supposed "PIM5" to a "PIM7." The present study indicates that these putative PIMs are in fact members of the phosphorus-free LOS family of glycolipids and that the protein product of Rv1500, which we have now termed LosA, is a glycosyltransferase involved in transferring sugars to LOS-III to form LOS-IV of M. marinum.

Base Sequence↗
PubMed2005

Self-organized Boolean game on networks.

A model of a Boolean game with only one free parameter p that denotes the strength of local interaction is proposed wherein each agent acts according to the information obtained from his neighbors in the network, and those in the minority are rewarded. The simulation results indicate that the dynamic of the system is sensitive to network topology, whereby the network of larger degree variance, i.e., the system of greater information heterogeneity, leads to less system profit. The system can self-organize to a stable state and perform better than the random choice game, although only the local information is available to the agents. In addition, in heterogeneity networks, the agents with more information gain more than those with less information for a wide extent of interaction strength p.

Journal Article↗
PubMed2005

Methylation protects miRNAs and siRNAs from a 3'-end uridylation activity in Arabidopsis.

Small RNAs of 21-25 nucleotides (nt), including small interfering RNAs (siRNAs) and microRNAs (miRNAs), act as guide RNAs to silence target-gene expression in a sequence-specific manner. In addition to a Dicer homolog, DCL1, the biogenesis of miRNAs in Arabidopsis requires another protein, HEN1. miRNAs are reduced in abundance and increased in size in hen1 mutants. We found that HEN1 is a miRNA methyltransferase that adds a methyl group to the 3'-most nucleotide of miRNAs, but the role of miRNA methylation was unknown. Here, we show that siRNAs from sense transgenes, hairpin transgenes, and transposons or repeat sequences, as well as a new class of siRNAs known as trans-acting siRNAs, are also methylated in vivo by HEN1. In addition, we show that the size increase of small RNAs in the hen1-1 mutant is due to the addition of one to five U residues to the 3' ends of the small RNAs. Therefore, a novel uridylation activity targets the 3' ends of unmethylated miRNAs and siRNAs in hen1 mutants. We conclude that 3'-end methylation is a common step in miRNA and siRNA metabolism and likely protects the 3' ends of the small RNAs from the uridylation activity.

Amino Acid Sequence↗
PubMed2005

The HMX homeodomain protein MLS-2 regulates cleavage orientation, cell proliferation and cell fate specification in the C. elegans postembryonic mesoderm.

The proper formation of a complex multicellular organism requires the precise coordination of many cellular events, including cell proliferation, cell fate specification and differentiation. The C. elegans postembryonic mesodermal lineage, the M lineage, allows us to study mechanisms coordinating these events at single cell resolution. We have identified an HMX homeodomain protein MLS-2 in a screen for factors required for M lineage patterning. The MLS-2 protein is present in nuclei of undifferentiated cells in the early M lineage and in a subset of head neurons. In the M lineage, MLS-2 activity appears to be tightly regulated at the fourth round of cell division, coincident with the transition from proliferation to differentiation. A predicted null allele of mls-2, cc615, causes reduced cell proliferation in the M lineage, whereas a semi-dominant, gain-of-function allele, tm252, results in increased cell proliferation. Loss or overexpression of mls-2 also affects cleavage orientation and cell fate specification in the M lineage. We show that the increased cell proliferation in mls-2(tm252) mutants requires CYE-1, a G1 cell cycle regulator. Furthermore, the C. elegans Myod homolog HLH-1 acts downstream of mls-2 to specify M-derived coelomocyte cell fates. Thus MLS-2 functions in a cell type-specific manner to regulate both cell proliferation and cell fate specification.

Amino Acid Sequence↗
PubMed2005

Expression of a novel apoptosis inhibitor-survivin in colorectal carcinoma.

AIM: To investigate the role of survivin expression in the pathogenesis of colorectal carcinoma. METHODS: Immunohistochemistry S-P method and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) were used to detect the expression of survivin and apoptotic cell in situ in colorectal cancerous tissues, para-cancerous tissues and normal tissues of 48 cases of colorectal carcinoma. RESULTS: The survivin positive unit (PU) was higher in cancerous tissues (38.76+/-5.14) than in para-cancerous (25.17+/-7.26) or normal tissues (0.57+/-0.03) (P<0.05). The apoptosis index (AI) of para-cancerous tissues was (7.51+/-2.63%) higher than cancerous tissues (4.65+/-1.76%). The expression of survivin was associated with pathological grade, lymph node metastasis and Dukes stage of colorectal carcinoma. CONCLUSION: Survivin expression may play an important role in carcinogenesis of colorectal carcinoma and may be associated with malignant biological behaviors of colorectal carcinoma.

Adult↗
PubMed2005

Requirement for tumor necrosis factor-receptor 2 in alveolar chemokine expression depends upon the form of the ligand.

Respiratory virus infection evokes a potent T-cell response that may result in a considerable insult to the structural and functional integrity of the gas exchange units of the lung. Alveolar antigen recognition by CD8+ T lymphocytes results in significant injury that is critically dependent upon tumor necrosis factor (TNF)-alpha expressed by the CD8+ T cells and is largely dependent upon TNF-receptor 1 expression on the alveolar epithelial target cells. TNF-receptor 2 (TNF-R2)-deficient mice were used to demonstrate that CD8+ T-cell-mediated lung injury associated with clearance of experimental influenza requires TNF-R2 for full expression of immunopathology. In vitro analysis indicates that alveolar cell expression of TNF-R2 is critical in the induction of epithelial monocyte chemoattractant protein (MCP)-1 expression specifically in response to soluble TNF-alpha, suggesting an important role for this receptor in bystander lung injury. However, TNF-R2 was dispensable for induction of alveolar MCP-1 expression in response to transmembrane TNF-alpha expressed by antigen-specific CD8+ T cells, and the effects of the two receptors seem to be additive. Because TNF-R2 may be rapidly shed as part of feedback inhibition of bystander inflammation, this suggests a mechanism by which immunopathology in respiratory virus infection may be regulated and by which T-cell receptor-dependent TNF-alpha activity might bypass such negative regulation for contact-dependent antiviral activities.

Animals↗