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Biomedical subjects

Bo Liu

Publications and source records attributed to Bo Liu.

At least 163 records · Page 9Linked to original sources
PubMed2003

More stringent conditions of plasmid DNA vaccination are required to protect grafted versus endogenous islets in nonobese diabetic mice.

Recurrent autoimmune destruction of the insulin-producing beta cells is a key factor limiting successful islet graft transplantation in type I diabetic patients. In this study, we investigated the feasibility of using an Ag-specific plasmid DNA (pDNA)-based strategy to protect pro-islets that had developed from a neonatal pancreas implanted under the kidney capsule of nonobese diabetic (NOD) mice. NOD recipient mice immunized with pDNA encoding a glutamic acid decarboxylase 65 (GAD65)-IgFc fusion protein (JwGAD65), IL-4 (JwIL4), and IL-10 (pIL10) exhibited an increased number of intact pro-islets expressing high levels of insulin 15 wk posttransplant, relative to NOD recipient mice immunized with pDNA encoding a hen egg lysozyme (HEL)-IgFc fusion protein (JwHEL)+JwIL4 and pIL10 or left untreated. Notably, the majority of grafted pro-islets detected in JwGAD65+JwIL4- plus pIL10-treated recipients was free of insulitis. In addition, administration of JwGAD65+JwIL4+pIL10 provided optimal protection for engrafted islets compared with recipient NOD mice treated with JwGAD65+JwIL4 or JwGAD65+pIL10, despite effective protection of endogenous islets mediated by the respective pDNA treatments. Efficient protection of pro-islet grafts correlated with a marked reduction in GAD65-specific IFN-gamma reactivity and an increase in IL-10-secreting T cells. These results demonstrate that pDNA vaccination can be an effective strategy to mediate long-term protection of pro-islet grafts in an Ag-specific manner and that conditions are more stringent to suppress autoimmune destruction of grafted vs endogenous islets.

Animals↗
PubMed2003

[Cervical posterior laminoplasty operation using T-saw and coralline hydroxyapatite spacer].

OBJECTIVE: To assess the efficacy of using T-saw and coralline hydroxyapatite (CHA) spacer in the cervical spinous process-splitting laminoplasty. METHODS: 38 patients were operated with cervical laminoplasty using T-saw and CHA spacer, among them there were 31 multisegmental cervical spondylotic myelopathy patients, 5 ossification of posterior longitudinal ligament (OPLL) patients, 2 anterior fusion failure patients. All the patients were evaluated by JOA scores. RESULTS: we followed the 38 patients for average 26 months. Numbness,strength and gait were improved obviously. The flat rate of spinal cord in MRI improved 0.23;CHA fusion percentage 74%; no primary spinal cord injury was found. Average operation time was 2 hour 50 min;average bleeding during the operation was 280 ml; The average JOA score improve rate was 61%. CONCLUSION: The methods, using T-saw and CHA spacer in the cervical spinous process-splitting laminoplasty, which was characterized by simple, short time on operation and thorough decompression of spinal cord, was a ideal optional method in the cervical laminoplasty operation.

Adult↗
PubMed2003

[Purification and study of the characteristics of the multinucleated giant cells of the giant cell tumor].

OBJECTIVE: To harvest high purified osteoclast-like giant cells from the giant cell tumor by using trypsin and EDTA(ethylenediamineteraacetic acid) digestion. And explore the role and the origin of the multinucleated giant cells of the giant cell tumor. METHODS: Multinucleated giant cells were isolated and cultured from 8 cases of giant cell tumor of the long bone. After 20 hours of culture, 0.5 g.L-1 trypsin/0.2 g.L-1 EDTA was applied to detach the mononuclear stromal cells. The isolated multinucleated giant cells were inoculated on dentine slice to observe bone resorption ability in vitro. Immunohistochemistry study with V-ATPase, CA II (carbonic anhydrate II), cathepsin K, MMP-9 (matrix metalloproteinase-9), CD68 and TRAP(tartrate-resistant acid phosphatase) staining were carried out in the purified multinucleated giant cells. RESULTS: We obtained 85% purified multinucleated giant cells by trypsin/EDTA digestion. Multinucleated giant cells formed resorption lacunae on dentine slice in vitro and positively stained for V-ATPase, CA II, cathepsin K and MMP-9. The TRAP staining was also positive. CONCLUSION: Using 0.5 g.L-1 trypsin/0.2 g.L-1 EDTA digestion can get high purified multinucleated giant cells from the giant cell tumor. The multinucleated giant cells match all the character of the osteoclast and may originate from the fusion of the mononuclear stromal cells of the lesion.

Bone Neoplasms↗
PubMed2003

[Cochlear implantation in patients with inner ear malformations, clinical analysis of 25 cases].

OBJECTIVE: To explore the clinical experience of multi-channel cochlear implantation in patients with bilateral inner ear malformations. METHOD: Multi-channel cochlear implantation was conducted among 180 patients from 1997 to 2001. Twenty-five of them, being with inner ear malformations, were given hearing and speech rehabilitation including sound detection, word discrimination, auditory comprehension and spoken language skill development. A follow-up lasting 4 - 24 months was conducted after the operation. A retrospective analysis was performed among these 25 patients to observe the surgical outcomes and mapping characteristics after surgery. RESULTS: (1) All patients restored their auditory sensations after the operation. (2) Stapedial gusher was found in 13 cases with inner ear malformations, especially those with Mondini malformation, much more frequently than among the patients with other malformations. (3) Most of the action electrodes were inserted in the "cochleostomy" in full length, only 2 pairs of them remained outside of the "cochleostomy". (4) No serious complications occurred after implantation. (5) The impedance of the electrodes, T level and C level were higher in the 25 cases than in the normal cochlear implantation, however, with the hearing similar hearing threshold. (6) After training, the abilities of speech discrimination and spoken language were improved in comparison with those before operation. CONCLUSION: The cochlear implantation can be performed safely in patients with bilateral inner ear malformations. The primary outcome of cochlear implantation in hearing rehabilitation is similar for both the patients with inner ear malformations and those with normal cochlear structure.

Adolescent↗
PubMed2003

Comparison of potassium currents in human decidua before and after the onset of labor.

The human decidua plays a prominent role in the signaling between maternal and fetal tissues. It also secretes a plethora of molecules that modulate uterine function. Ion-channel activity underpins many cellular functions; however, the channels in human decidua have not been characterized in any detail. We have used the whole-cell recording mode of the patch-clamp technique to carry out current-clamp and voltage-clamp recordings of membrane properties and whole-cell potassium (K+) currents of freshly isolated decidual stromal cells. Decidual tissue was obtained from women after spontaneous vaginal delivery (SVD) or elective cesarean section (CS). Cells from both groups generated action potentials, the overshoots and durations of which were dependent on extracellular calcium levels, inhibited by cobalt and enhanced by barium. Potassium current (IK) density was higher in the CS than in the SVD group. Outwardly directed currents were heterogeneous with respect to their activation/inactivation profiles and exhibited outward rectification. The main difference between the SVD and CS group was the presence of a sustained current component in CS cells that is tetraethylammonium chloride-resistant and appears to be unaffected by E-4031. No evidence for the activation of any calcium-activated K+ currents was obtained. We propose that human parturition is associated with subtle changes in K+ channel remodeling, reflecting the transition from uterine quiescence to activation and stimulation. An understanding of the signal transduction events underlying these process may eventually lead to novel approaches to prevent preterm labor via decidual rather than myometrial intervention.

4-Aminopyridine↗
PubMed2003

TGF-beta stimulates collagen (I) in vascular smooth muscle cells via a short element in the proximal collagen promoter.

BACKGROUND: Accumulation of extracellular matrix contributes to the development of intimal hyperplasia. Transforming growth factor beta (TGF-beta) stimulates the production of several matrix proteins in vascular smooth muscle cells (SMC) including type I collagen, but the underlying mechanisms of TGF-beta's effects are not well understood. MATERIALS AND METHODS: The effect of TGF-beta on type I collagen biosynthesis was determined by a [3H]proline incorporation assay and Northern blotting. The promoter of human alpha2(I) procollagen (COL1A2) gene was analyzed by transient transfection analysis and gel mobility shift assay. RESULTS: Treatment of human vascular SMC with TGF-beta stimulated collagen synthesis and increased the level of alpha2(I) collagen mRNA. A collagen-luciferase reporter gene, constructed by linking the human COL1A2 promoter with the firefly luciferase gene, was transiently expressed in human SMC. Treatment with TGF-beta significantly stimulated the activity of this collagen-luciferase reporter. Using deletion analysis, we identified a 150 bp DNA fragment (-334 to -184) in the human COL1A2 promoter as the site through which TGF-beta mediates collagen gene expression in human SMC. Gel mobility shift assays demonstrated that this 150 bp DNA fragment formed conjugates with multiple nuclear factors derived from SMC, a process that was further enhanced by TGF-beta. CONCLUSIONS: TGF-beta stimulates the human type I collagen gene via a DNA element located in the proximal region of its promoter. Interventions that disrupt interaction between this DNA element and nuclear factors may block the production of collagen in response to TGF-beta and consequently may have a significant effect on the development of intimal hyperplasia.

Binding Sites↗
PubMed2003

Multinucleated giant cells in various forms of giant cell containing lesions of the jaws express features of osteoclasts.

BACKGROUND: The nature and the mechanism involved in the formation of the multinucleated giant cells (MGCs) in various giant cell-containing lesions of the jaws are not fully understood. The aim of this study is to clarify the osteoclastic features of the MGCs in central giant cell granuloma (CGCG), peripheral giant cell granuloma (PGCG), cherubism, and aneurysmal bone cyst (ABC), and the mechanism underlying the interrelations between cellular components in the formation of the MGCs. METHODS: Immunohistochemical study with a panel of antibodies including vacuolar H+-ATPase (V-ATPase), carbonic anhydrase II (CA II), Cathepsin K, matrix metalloproteinases-9 (MMP-9), CD68, and proliferating cell nuclear antigen (PCNA), and enzyme histochemical staining for tartarate-resistant acid phosphatase (TRAP) were applied on a total number of 53 cases of giant cell-containing lesions including CGCG (n = 34), PGCG (n = 6), cherubism (n = 7), and ABC (n = 6). In situ hybridization was also carried out to detect the mRNA expression of the receptor activator of NF-kappaB ligand (RANKL), a newly identified cytokine that is shown to be essential in the osteoclastogenesis, its receptor RANK (receptor activator of NF-kappaB ligand), and its decoy receptor OPG (osteoprotegerin) in these four types of lesions. RESULTS: Immunohistochemical and enzyme histochemical studies showed that both the MGCs and a fraction of mononuclear cells in these lesions were strongly positive for TRAP, V-ATPase, CA II, Cathepsin K, MMP-9, and CD68, while the spindle-shaped mononuclear cells were positive for PCNA. The results with in situ hybridization indicated that RANKL mRNA was mainly expressed in the spindle mononuclear cells while OPG was extensively distributed in both the MGCs and the mononuclear cells. RANK mRNA was expressed in the MGCs and some round mononuclear cells. CONCLUSIONS: These results suggest that MGCs in the four types of giant cell-containing lesions of the jaws show characteristics of the osteoclast phenotype. The mononuclear stromal cells, which show TRAP positively, may be the precursors of the MGCs. RANKL, OPG, and RANK expressed in these lesions may play important roles in the formation of the MGCs. The similar characteristics and mechanisms in the differentiation of MGCs in these lesions also suggest that there might be a similar kind of pathogenesis involved in the formation of the MGCs in these lesions

Bone Cysts, Aneurysmal↗
PubMed2003

The requirement of the LC8 dynein light chain for nuclear migration and septum positioning is temperature dependent in Aspergillus nidulans.

In the filamentous fungus Aspergillus nidulans, the multisubunit motor complex cytoplasmic dynein plays essential roles in nuclear migration and septum positioning. The 8 kDa light chain, LC8, the smallest subunit, is conserved among eukaryotic organisms. Besides being a component in the dynein complex, LC8 also interacts with a wide spectrum of mammalian and viral proteins. To date, the function of this small polypeptide is not well understood. To address this issue, we have created a deletion mutation (DeltanudG) at the nudG locus encoding LC8 in A. nidulans. At 42 degrees C, the DeltanudG mutant forms minute colonies lacking asexual reproduction: this phenotype resembles the phenotype of the dynein heavy chain null mutant. The mutant nuclei largely clustered in the spore body after conidial germination, and the septum was often assembled distally toward the hyphal apex, whereas a control germling has its nuclei distributed along the hypha and the septum formed near the spore body. When the mutant was grown at 23 degrees C, however, its colony resembled a control one, and so did the patterns of nuclear distribution and septum positioning. Elevation of the growth temperature gradually reduced colony size and abolished asexual sporulation. After a period of growth at 23 degrees C that allowed the nuclei to move out of the spore end, a temperature shift to 42 degrees C prevented newly divided nuclei from migrating apart, suggesting that LC8/NUDG was required for both initiating and maintaining dynein motor functions at elevated temperatures. A functional GFP-NUDA fusion was used to test whether LC8/NUDG is required for DHC (dynein heavy chain)/NUDA localization. We found that at 23 degrees C GFP-NUDA localized to the hyphal apex and the septation site in DeltanudG cells as in control cells. Such localizations were absent at 42 degrees C in mutant cells, but not in control cells. We conclude that LC8 plays a role in DHC localization/function, and the requirement for such a role in A. nidulans cells is temperature dependent.

Aspergillus nidulans↗
PubMed2003

The cotton kinesin-like calmodulin-binding protein associates with cortical microtubules in cotton fibers.

Microtubules in interphase plant cells form a cortical array, which is critical for plant cell morphogenesis. Genetic studies imply that the minus end-directed microtubule motor kinesin-like calmodulin-binding protein (KCBP) plays a role in trichome morphogenesis in Arabidopsis. However, it was not clear whether this motor interacted with interphase microtubules. In cotton (Gossypium hirsutum) fibers, cortical microtubules undergo dramatic reorganization during fiber development. In this study, cDNA clones of the cotton KCBP homolog GhKCBP were isolated from a cotton fiber-specific cDNA library. During cotton fiber development from 10 to 21 DPA, the GhKCBP protein level gradually decreases. By immunofluorescence, GhKCBP was detected as puncta along cortical microtubules in fiber cells of different developmental stages. Thus our results provide evidence that GhKCBP plays a role in interphase cell growth likely by interacting with cortical microtubules. In contrast to fibers, in dividing cells of cotton, GhKCBP localized to the nucleus, the microtubule preprophase band, mitotic spindle, and the phragmoplast. Therefore KCBP likely exerts multiple roles in cell division and cell growth in flowering plants.

Amino Acid Sequence↗
PubMed2003

[Glycocorticosteroid administration prevents fulminant hepatic failure occurrence in patients with chronic hepatitis B of severe degree].

OBJECTIVE: To prevent chronic severe hepatitis, even more fulminant hepatic failure (FHF) occurrence in patients with chronic hepatitis B of severe degree using steroid. METHODS: 120 patients were randomized into conventional supporting treatment and steroid treatment groups. The latter, 62 patients were given intravenously hydrocortisone sodium succinate at the dose of 150 mg to approximately 200 mg everyday plus support care. RESULTS: The rate of deteriorating to chronic severe hepatitis in steroid treatment group was significantly lower than that of conventional group (22% vs 48%, x(2) =7.60, P<0.01). 53.6% (15/28) patients with chronic severe hepatitis in conventional group died, while only 28.6% (4/14) in steroid treatment group succumbed to terminal liver disease (x(2)=0.02, P>0.05). There was no difference between the two groups regarding to complications incidence: gastrointestinal bleeding and infections except for some controllable serious reverse events, such as candidiasis, diabetes, herpes zoster and pulmonary tuberculosis found in some patients in steroid-treated group. CONCLUSION: These results suggest that steroid administration with improved support care not only is likely to prevent chronic severe hepatitis occurrence in patients with chronic viral hepatitis of severe degree, but also shows some efficacy for FHF, which warrant further investigation.

Adult↗
PubMed2003

[Cochlear implants in children with enlargement of vestibular aqueduct].

OBJECTIVE: To describe the clinical experiences with multi-channel cochlear implantation in the children with enlargement of vestibular aqueduct. METHOD: Fifteen patients were diagnosed with enlargement of vestibular aqueduct and received multi-channel cochlear implantation at Beijing Tongren Hospital. A cochleostomy was performed for all patients by a standard facial recess approach to anterior inferior to the round window niche. RESULTS: (1) Most of the electrodes were totally inserted in the cochlear, and gusher appeared in 6 implantations. (2) No serious complications occurred after implantation. (3) All patients have auditory sensations after implantations. (4) The hearing threshold in this series were similar to that of the normal cochlear implantation (the average threshold was 30 dB). (5) The rehabilitation concept was developed by Rehabilitation Research Center for Deaf Children in Beijing and Beijing Tongren Hospital. The training sessions included sound detection, word discrimination, auditory comprehension and spoken language skill development. The abilities of speech discrimination and spoken language were improved comparing with that of pre-operation. Two of the patients could go to the normal school after implantations. CONCLUSION: The outcome of hearing rehabilitation for children with enlargement of vestibular aqueduct were similar to those children with "normal" cochlear structure followed the multi-channel cochlear implantation.

Adolescent↗
PubMed2003

[Treatment of portal hypertension by endoscopic esophageal ligation of varicose veins combined with partial splenic embolization].

OBJECTIVE: To evaluate the feasibility and efficacy of a new method of endoscopic esophageal variceal ligation combined with partial splenic embolization (EVL-PSE) for the patients with portal hypertension. METHODS: From May 1999 to February 2003, sixty-eight patients with portal hypertension underwent EVL-PSE, and hemodynamics of the portal trunk (PT), the left gastric vein and azygos vein, including maximum velocity, flow volume, vein diameter, were assessed using color ultrasound Doppler. RESULTS: The esophageal varices and hypersplenism were greatly ameliorated after operation in patients who had undergone EVL-PSE. Postoperative portal trunk flow volume and velocity were significantly reduced (P < 0.05), and flow volume of the left gastric vein as well as the azygos vein were also reduced after operation. During 2 - 24-month follow-up, no recurrent bleeding was found. CONCLUSIONS: EVL-PSE is less traumatic with less complications, and results in marked eradication of esophageal varices, it can be carried out safely in the clinical treatment for patients with portal hypertension.

Adult↗
PubMed2002

The first inner loop of endothelin receptor type B is necessary for specific coupling to Galpha 13.

Endothelin (EDN) receptor type B (EDNRB) activates serum response factor (SRF) via G(q/11) and G(12/13) G proteins. In this study, we investigated the involvement of intracellular loop sequences of EDNRB in coupling to these G proteins. EDNRB mutants were generated and tested for their abilities to activate SRF in NIH3T3 cells and in the mouse embryonic fibroblast cell line (F(q/11)) lacking both Galpha(q) and Galpha(11). EDNRB can activate SRF in NIH3T3 cells via G(q/11), although it can only activate SRF through G(12/13) in F(q/11) cells. Mutants with mutations in the second and third inner loops of EDNRB functioned in the same manner in both cell lines, either able or unable to activate SRF. This finding suggests that the second and third inner loops of EDNRB either participate or not in coupling to both G(q/11) and G(12/13) but are not specific for either one. However, in the first inner loop, a substitution of three Ala residues for Met(128)-Arg(129)-Asn(130) abolished the ability to activate SRF only in F(q/11) cells, suggesting that this mutation might specifically disrupt the coupling to G(12/13) rather than to G(q/11). Further characterization of this first inner loop mutant revealed that exogenous expression of Galpha(12) or Galpha(q) could restore SRF activation, whereas the expression of Galpha(13) did not. Therefore, we conclude that although the three intracellular loops of EDNRB may be involved in coupling to G proteins, residues Met(128)-Arg(129)-Asn(130) in the first intracellular loop are specifically required for activation of Galpha(13).

3T3 Cells↗
PubMed2002

Fluorescence of cis-1-amino-2-(3-indolyl)cyclohexane-1-carboxylic acid: a single tryptophan chi(1) rotamer model.

A constrained derivative, cis-1-amino-2-(3-indolyl)cyclohexane-1-carboxylic acid, cis-W3, was designed to test the rotamer model of tryptophan photophysics. The conformational constraint enforces a single chi(1) conformation, analogous to the chi(1) = 60 degrees rotamer of tryptophan. The side-chain torsion angles in the X-ray structure of cis-W3 were chi(1) = 58.5 degrees and chi(2) = -88.7 degrees. Molecular mechanics calculations suggested two chi(2) rotamers for cis-W3 in solution, -100 degrees and 80 degrees, analogous to the chi(2) = +/-90 degrees rotamers of tryptophan. The fluorescence decay of the cis-W3 zwitterion was biexponential with lifetimes of 3.1 and 0.3 ns at 25 degrees C. The relative amplitudes of the lifetime components match the chi(2) rotamer populations predicted by molecular mechanics. The longer lifetime represents the major chi(2) = -100 degrees rotamer. The shorter lifetime represents the minor chi(2) = 80 degrees rotamer having the ammonium group closer to C4 of the indole ring (labeled C5 in the cis-W3 X-ray structure). Intramolecular excited-state proton transfer occurs at indole C4 in the tryptophan zwitterion (Saito, I.; Sugiyama, H.; Yamamoto, A.; Muramatsu, S.; Matsuura,T. J. Am. Chem. Soc. 1984, 106, 4286-4287). Photochemical isotope exchange experiments showed that H-D exchange occurs exclusively at C5 in the cis-W3 zwitterion, consistent with the presence of the chi(2) = 80 degrees rotamer in solution. The rates of two nonradiative processes, excited-state proton and electron transfer, were measured for individual chi(2) rotamers. The excited-state proton-transfer rate was determined from H-D exchange and fluorescence lifetime data. The excited-state electron-transfer rate was determined from the temperature dependence of the fluorescence lifetime. The major quenching process in the -100 degrees rotamer is electron transfer from the excited indole to carboxylate. Electron transfer also occurs in the 80 degrees rotamer, but the major quenching process is intramolecular proton transfer. Both quenching processes are suppressed by deprotonation of the amino group. The results for cis-W3 provide compelling evidence that the complex fluorescence decay of the tryptophan zwitterion originates in ground-state heterogeneity with the different lifetimes primarily reflecting different intramolecular excited-state proton- and electron-transfer rates in various rotamers.

Carboxylic Acids↗
PubMed2002

Expression and localization of human lysozyme in the endosperm of transgenic rice.

In order to understand the characteristics of recombinant protein expression and sublocalization in rice ( Oryza sativa L.) endosperm, we examined the expression level of human lysozyme protein and its subcellular location in transgenic rice seeds driven by rice glutelin and globulin promoters and signal peptides. A time course of human lysozyme expression during endosperm development was analyzed. The results showed that the expression profile of recombinant protein accumulation in endosperm paralleled that of the two storage proteins. Immunofluorescence microscopy revealed that human lysozyme and storage proteins co-localized to type-II protein bodies. Both promoter-signal peptide parings targeted recombinant protein to the protein bodies. In addition, a transgenic line with a higher lysozyme expression level exhibited morphologically different protein bodies with an unbalanced composition of lysozyme and native storage proteins. The high-level expression of recombinant protein distorted the trafficking and sorting of native storage proteins in rice endosperm and affected the expression of native storage protein.

Gene Expression Regulation, Enzymologic↗
PubMed2002

Herbicide and insecticide loadings from the Susquehanna River to the northern Chesapeake Bay.

The Susquehanna River watershed has a large drainage area (71200 km(2)) containing heavy agricultural land usage. The river provides approximately half the total freshwater input to the Chesapeake Bay. Water samples were collected at Conowingo Dam near the mouth of the river every 9 days from February 1997 through March 1998. Atrazine, its transformation product 6-amino-2-chloro-4-(isopropylamino)-s-triazine (CIAT), and metolachlor were found in the highest concentrations with maximums of 500, 150, and 330 ng/L, respectively. The annual mass loads for atrazine, CIAT, metolachlor, simazine, and 6-amino-2-chloro-4-(ethylamino)-s-triazine (CEAT) from the Susquehanna River to the Chesapeake Bay were 1600, 1600, 1100, 820, and 720 kg/year, respectively. Annual loadings of insecticides and organochlorine compounds ranged from 2.8 kg/year for alpha-HCH to 34 kg/year for diazinon. Strong correlations between loading data from this and previous studies and total annual water discharge through the dam were used to estimate total metolachlor and atrazine loads (12400 and 9950 kg, respectively) to the northern Chesapeake Bay from 1992 to 1997.

Acetamides↗