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Biomedical subjects

Juan Li

Publications and source records attributed to Juan Li.

At least 55 records · Page 3Linked to original sources
PubMed2006

Pharmacological profile of PMS777, a new AChE inhibitor with PAF antagonistic activity.

The key pathophysiological mechanisms in Alzheimer's disease involve the selective loss of cholinergic neurons and pro-inflammatory mediator-related chronic inflammatory responses in the brain, therefore interventions of these processes are crucial to the treatment of this disease. In the present study, the pharmacological profile of PMS777, a new acetylcholinesterase (AChE) inhibitor with platelet-activating factor (PAF) antagonistic activity, has been evaluated in vitro and in vivo. PMS777 (1-100 microM) dose-dependently inhibited PAF-induced rabbit platelet aggregation by competing with [3H]PAF for its receptor on platelets, and protected a human neuroblastoma cell line SH-SY5Y against PAF-induced neurotoxicity. Moreover, it markedly inhibited brain AChE activity in mice and showed a modest selectivity for AChE (AChE: IC50=2.48+/-0.12 microM; butyrylcholinesterase: IC50=4.47+/-0.15 microM). Ex vivo, PMS777 (5, 10, 20 or 40 mg/kg i.p.) reduced brain AChE activity in a dose-dependent manner. In-vivo studies revealed that PMS777 (0.25, 0.5, 1, 2.5 or 5 mg/kg i.p.) could reverse scopolamine-induced memory retrieval deficits in mice, and displayed a typical bell-shaped dose-response relationship. Taken together, these results demonstrate that PMS777 possesses dual activities for PAF receptor antagonism and AChE inhibition, suggesting that this compound may be a promising lead compound for further investigation related to the treatment for Alzheimer's disease.

Acetylcholinesterase↗
PubMed2006

Synthesis and anti-tumor activities of novel pyrazolo[1,5-a]pyrimidines.

A series of novel pyrazolo[1,5-a]pyrimidines were designed and synthesized in order to find novel potent anti-tumor compounds. The structures of all the compounds were confirmed by IR, (1)H-NMR, elemental analysis, and MS. Their anti-tumor activities against cancer cell lines were tested by the MTT method in vitro. Compound 19 displayed potent anti-tumor activity.

Antineoplastic Agents↗
PubMed2006

A CR1 element is embedded in a novel tandem repeat (HinfI repeat) within the chicken genome.

Highly repetitive DNA sequences constitute a significant portion of most eukaryotic genomes, raising questions about their evolutionary origins and amplification dynamics. In this study, a novel chicken repetitive DNA family, the HinfI repeat, was characterized. The basic repeating unit of this family displays a uniform length of 770 bp, which was defined by the recognition site of HinfI. The HinfI repeat was specifically localized in the pericentric region of chromosome 4 by fluorescence in situ hybridization and constitutes 0.51% of the chicken genome. Interestingly, a chicken repeat 1 (CR1) element has been identified within this basic repeating unit. Like other CR1 elements, this CR1 element also displays typical retrotransposition characteristics, including a highly conserved 3' region and a badly truncated 5' end. This direct evidence from sequence analysis, together with our Southern blot results, suggests that the HinfI repeat may originate from a unique region containing a retrotransposed CR1 element.

Animals↗
PubMed2006

Neuroanatomic organization of sound memory in humans.

The neural interface between sensory perception and memory is a central issue in neuroscience, particularly initial memory organization following perceptual analyses. We used functional magnetic resonance imaging to identify anatomic regions extracting initial auditory semantic memory information related to environmental sounds. Two distinct anatomic foci were detected in the right superior temporal gyrus when subjects identified sounds representing either animals or threatening items. Threatening animal stimuli elicited signal changes in both foci, suggesting a distributed neural representation. Our results demonstrate both category- and feature-specific responses to nonverbal sounds in early stages of extracting semantic memory information from these sounds. This organization allows for these category-feature detection nodes to extract early, semantic memory information for efficient processing of transient sound stimuli. Neural regions selective for threatening sounds are similar to those of nonhuman primates, demonstrating semantic memory organization for basic biological/survival primitives are present across species.

Acoustic Stimulation↗
PubMed2006

Characterization of lesions of the talus and description of tram-track lesions.

BACKGROUND: The ankle joint, although not prone to primary osteoarthritis (OA), is known to be susceptible to secondary OA as a result of sports injuries and other trauma. Unlike the knee joint, a thorough investigation of talar cartilage lesions has not been previously reported. METHODS: One hundred and five human tali from 67 donors were used to determine the type and location of the most common lesions through gross examination, radiography, diffraction enhanced imaging, and histology. "tram-track lesions" also are described. RESULTS: The most anterior and posterior regions of the talar dome, along with the medial and lateral borders of the dome were most affected by cartilage degeneration. These are regions that appear to be most subjected to frictional forces from their articulating counterparts during high stress activities that move articulating surfaces slightly out of congruence with each other. One particularly striking cartilage degeneration pattern that, to our knowledge, has not been described histologically, is the tram-track lesion. These lesions displayed a longitudinally oriented groove in the cartilage, running from anterior to posterior, in which the deepest portion of the groove was located in the middle of the anterior-posterior axis of the talus. Several of these cartilage grooves had a bony ridge beneath, mirroring the cartilage groove whereas others did not. This suggests that the cartilage groove develops before the interruption of the tidemark (border between the calcified and uncalcified cartilage). In specimens for which the articulating tibial articular surface was available, (17) it was found that the tibia displayed small osteophytes on the anterior articular margin that exactly corresponded to their articulation with the talar cartilage grooves as the ankle articulated through plantar flexion and dorsiflexion. CONCLUSION: This study provides an in-depth histologic and gross anatomic look at the most common lesions of the talus of the ankle joint. In particular, the "tram-track" lesion was shown to be a consequence of its tibial articulation and to include both subchondral bone and articular cartilage changes.

Adult↗
PubMed2006

Differential response of the epithelium and interstitium in developing human fetal lung explants to hyperoxia.

Hyperoxia is closely linked with the development of chronic lung disease of prematurity (CLD), but the exact mechanisms whereby hyperoxia alters the lung architecture in the developing lung remain largely unknown. We developed a fetal human lung organ culture model to investigate (a) the morphologic changes induced by hyperoxia and (b) whether hyperoxia resulted in differential cellular responses in the epithelium and interstitium. The effects of hyperoxia on lung morphometry were analyzed using computer-assisted image analysis. The lung architecture remained largely unchanged in normoxia lasting as long as 4 d. In contrast, hyperoxic culture of pseudoglandular fetal lungs resulted in significant dilatation of airways, thinning of the epithelium, and regression of the interstitium including the pulmonary vasculature. Although there were no significant differences in Ki67 between normoxic and hyperoxic lungs, activated caspase-3 was significantly increased in interstitial cells, but not epithelial cells, under hyperoxic conditions. These changes show that exposure of pseudoglandular lungs to hyperoxia modulates the lung architecture to resemble saccular lungs.

Apoptosis↗
PubMed2006

Widespread and stable pancreatic gene transfer by adeno-associated virus vectors via different routes.

Diabetes is a disease of epidemic proportions and is on the rise worldwide. Gene therapy has been actively pursued but limited by technical hurdles and profound inefficiency of direct gene transfer to the pancreas in vivo. Here, we show that, for the first time, appropriate serotypes of adeno-associated virus (AAV), coupled with a double-stranded vector DNA cassette, enable extensive and long-term in vivo gene transfer in the adult mouse pancreas by three different delivery methods. Intraperitoneal and intravenous delivery of AAV8 effectively transduced exocrine acinar cells as well as endocrine beta-cells, while local pancreatic intraductal delivery of AAV6 showed the best efficiency in the beta-cells among all AAV serotypes tested in this study. Nearly the entire islet population showed gene transfer but with distinct gene transfer efficiency and patterns when different delivery methods and vectors were used. Importantly, localized gene delivery coupled with an insulin promoter allowed extensive yet specific gene expression in the beta-cells. These effective new methods should provide useful tools to study diabetes pathogenesis and gene therapy.

Actins↗
PubMed2006

[Differential response of developing human fetal lung explants to hyperoxia and the effects of dexamethasone on hyperoxia-exposed lungs].

OBJECTIVE: This study aimed to explore the effects of hyperoxia on the development of fetal lung by investigating the changes of morphological and cell proliferation induced by hyperoxia in cultured fetal lungs as well as the effects of dexamethasone on hyperoxia-exposed lungs. METHODS: Human fetal lung explants at the pseudoglandular stage of development were cultured randomly either in normoxia (21% O2/5% CO2) or hyperoxia (95% O2/5% CO2) for 72 hrs. Dexamethasone was added into the feeding medium at the concentration of 10(-6)M. Harvested tissues were stained for pancytokeratin to identify epithelial cells, with Ki-67 as a marker of proliferation. The effects of lung morphometry were analyzed using computer assisted image analysis. The mean airway thickness, the proportion of the surface area occupied by airways, the mean airway surface area and the index of the epithelium proliferation were measured. RESULTS: The lung architectures remained unchanged after 72 hrs normoxia culture, whereas hyperoxia culture resulted in significant dilation of airways and thinning of epithelium, with the surface area of airways of 6662 microm(2) vs 2728 microm(2) and the thickness of airways of 7.8 microm vs 8.1 microm (P < 0.05). Hyperoxia culture also resulted in an increase in the proportion of the surface area occupied by airways than normoxia culture (35.2% vs 23.4%; P < 0.05). The surface area of airways (3174 microm(2)) and the proportion of the surface area occupied by airways (23.9%) decreased significantly in hyperoxia-cultured lungs after dexamethasone administration (P < 0.05). The epithelium proliferation index in hyperoxia-cultured lungs (21.8%) was higher than that in normoxia-cultured lungs (5.1%) and dexamethasone-treated hyperoxia-cultured lungs (7.4%) (P < 0.05). CONCLUSIONS: The exposure of pseudoglandular lungs to hyperoxia modulates the lung architecture to resemble saccular lungs with higher epithelium proliferation index. Dexamethasone may inhibit the effects induced by hyperoxia.

Cell Differentiation↗
PubMed2006

[Etiology of laryngeal stridor in neonates: analysis of 16 cases].

OBJECTIVE: To reduce misdiagnosis and explore etiology of laryngeal stridor in neonates. METHODS: Sixteen neonates with laryngeal stridor were reviewed. All the patients were examined with CT scan for larynx and lungs and some were examined with laryngoscopy. Laboratory examination and chromosome analysis were also done in all or some patients. RESULTS: All the 16 neonates were diagnosed before admission as congenital simple laryngeal stridor in other hospitals. Of the 16 neonates with laryngeal stridor, 5 (31%) had thyroglossal ductal cyst, 1 (6%) neonate with cri du chat (5p(-)) syndrome, 2 (13%) neonates with Pierre-Robin syndrome and the rest 8 (50%) were suspected of congenital simple laryngeal stridor. CONCLUSION: Neonates with laryngeal stridor are easily misdiagnosed; neonatal thyroglossal duct cyst is one of common causes. The diagnosis for a congenital simple laryngeal stridor should be carefully made excluding the possibility of related diseases. The authors recommend that laryngoscopy and CT scan for larynx should be performed in the neonates with laryngeal stridor.

Diagnostic Errors↗
PubMed2006

[Computer-aided mandibular repositioning system for efficacy prediction of oral appliance in patients with obstructive sleep apnea-hypopnea syndrome].

OBJECTIVE: To develop a computer-aided mandibular repositioning system (CAMRS) and investigate its preliminary application in efficacy prediction of oral appliance in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). METHODS: CAMRS was mainly consisting of a step motor and a screw that was remote-controlled by a computer. This system could work with polysomnography (PSG). Fourteen OSAHS patients diagnosed by PSG were recruited. With CAMRS, six mandibular positions were titrated with PSG for every hour. RESULTS: Stable mandible positioning and little sleeping disturbance were observed. Apnea hypopnea index (AHI) was improved progressively with mandibular advancement. The extent of mandibular advancement was correlated with the severity of OSAHS (r = 0.72747). CONCLUSIONS: CAMRS could reproductively and effectively reposition mandible with little sleeping disturbance. Through CAMRS, an individualized optimal mandibular position could be obtained for each OSAHS patient treated with oral appliance.

Adult↗
PubMed2006

[Evaluation of procleix HIV/HCV RNA diagnostic assay].

BACKGROUND: To investigate the sensitivity and specificity of Procleix HIV/HCV RNA diagnostic assay. METHODS: HIV antibody positive or suspected positive plasmas of blood donors were collected from different provinces and detected with HIV antibody ELISA and HCV antibody ELISA. Samples positive for HIV by ELISA were confirmed by using HIV Blot. All the plasma samples were detected with Procleix HIV/HCV assay, HIV-1 discriminatory assay and HCV discriminatory assay, respectively. RESULTS: All 74 samples positive for both HIV and HCV antibody were positive and 5 samples negative for both HIV and HCV antibody were negative when detected using Procleix HIV/HCV assay; 82 of 84 supplemental HIV antibody positive samples and 6 of 12 supplemental indeterminate samples were positive for HIV RNA, and all 7 HIV antibody negative samples were negative for HIV RNA when detected by using Procleix HIV discriminatory assay. Seventy of 81 HCV antibody positive samples and 4 of 22 HCV antibody negative samples were positive for HCV RNA when detected by using Procleix HCV discriminatory assay. CONCLUSION: This reagent is more sensitive and could be used in blood screening, thereby can reduce both HIV and HCV transmission of blood in window period of HIV and HCV infection.

Blood Donors↗
PubMed2006

[Function of getting rid of cores of Cornus officinalis Sieb. et Zucc. and studies on method of processing in producing area].

OBJECTIVE: To gain a clear idea on function of getting fid of cores of Cornus officinalis Sieb. et Zucc. and elect a suitable processing method and technics of Crnus officinalis Sieb. et Zucc. in producing area. METHODS: The contents of loganin and morroniside were determined in the cores and sarocarp of Cornus officinalis Sieb. et Zucc.; Using pathogonal method, the methods which Cornus officinalis sieb. et Zuee. were warmed or poached were isolated by determining quantitively loganin from Cornus officinalis Sieb. et Zucc. by HPLC. RESULTS: There was a bit loganin and morroniside in the cores of Cornus officinalis Sieb. et Zuecc.; There were three aspects that were marked influence to extracted account of loganin which were hot temperature of poach, adding water and time of warming. The best suitable extracting technology was warmed in 60 degrees C by 10 min and then getted rid of cores. CONCLUSION: Clearing the non-medicinal positon is the function of getting rid of cores of Cornus officinalis Sieb. et Zucc. and warming is better than poach.

Chromatography, High Pressure Liquid↗
PubMed2006

[Effects of electroacupuncture on GDNF positive cell immunoreactivity in local dermal tissue of the inflammatory pain focus in the rat of adjuvant arthritis].

OBJECTIVE: To study on the analgesic mechanism of electroacupuncture (EA) in the rat of adjuvant arthritis (AA). METHODS: Forty-eight SD rats were randomly divided into a blank control group (n = 8), an inflammatory group (n = 10), an acupoint EA group (n = 10), a non-acupoint EA group (n = 10) and a contralateral acupoint EA group (n = 10). Complete Freund's adjuvant (CFA) 50 microL were injected into the left malleolus' articular cavity in the rats except the blank control group for preparing single local adjuvant arthritis (AA) model. EA was given every other day to the acupoint EA group, the non-acupoint EA group and the contralateral acupoint EA group. The improving effects of EA at "Huantiao" (GB 30) and "Yanglingquan" (GB 34) on the dorsal flexion pain score and the swell of dorsum of hind paw were investigated, and effects of EA on Glial cell line-derived neurotrophic factor (GDNF) positive cells immunoreactivity in the inflammatory tissue of the AA rats on the 14th day after injection of adjuvant were observed with immunohistochemical technique. RESULTS: Hyperalgesia and local swell, and GDNF in the dermal and subcutaneous tissue around the inflammatory ankle joint in the inflammatory groups were significantly higher than those in the blank control group. EA on the ipsilateral and contralateral acupoints reduced the pain, promoted the recovery of swell, and decreased the positive area percentage and mean optical density of GDNF positive cells in the dermal and the subcutaneous tissues. However, the non-acupoint EA group did not have this action. CONCLUSION: EA can regulate expression of GDNF in local dermal tissue of the inflammatory focus in the AA rat, so as to exert the anti-inflammatory and analgesic effects.

Animals↗
PubMed2006

[Effects of different recover and restoration measures on soil quality in Karst Rocky Desertification Region].

The soil quality of karst rocky desertification region were taken as case studies with four different recover and restoration measures for 13 years long-term fixed site harnessing in Guizhou Province, and plant diversity and soil fertility over different measures were investigated. The results showed that the plant diversity was the lowest, soil feritilities and ecosystem environment were the poorest in the control land with no restoration measure. The plant diversity rised evidently and the soil quality restorated to some degree in the measure of changing into a Zanthorylum bungeamum woods (Measure A) and the measure of changing into multispecies woods (Measure B). The diversity of auxiliary community were resumed to the best degree and soil quality were resumed to the best degree in measure of closed forest (Measure C). The plant diversity was higher and soil quality was best in measure of secondary forest (Measure D). Therefore, the proper biological measures and the essential engineering measures are effective to recover the serious degradation ecosystem in Karst mountain of Guizhou Province.

Conservation of Natural Resources↗
PubMed2006

An acquired translocation in JAK2 Val617Phe-negative essential thrombocythemia associated with autosomal spread of X-inactivation.

The acquired mutation Val617Phe in the tyrosine kinase JAK2 was recently identified in most but not all patients with classical myeloproliferative disorders. We describe a cytogenetic and molecular study of a JAK2Val617Phe-negative case of essential thrombocythemia harboring the acquired translocation t(X;5)(q13;q33). We show that this involves the inactive X-chromosome and is associated with silencing of autosomal genes within the adjacent 5q minus syndrome common deleted region. This is the first documented example of autosomal gene silencing adjacent to an X-autosome breakpoint in human malignancy and such a mechanism may underlie the pathogenesis of related disorders with translocations involving Xq13.

Amino Acid Substitution↗
PubMed2006

[RelB gene expression in murine bone marrow-derived mature and immature dendritic cells].

AIM: To explore the expression of avian reticuloendotheliosis viral(v-rel) oncogene-related B (RelB) mRNA in vitro in murine mature and immature myeloid dendritic cells (DCs). METHODS: The bone marrow was collected from the femur and tibias of C57BL/6 mice in sterile condition. Bone marrow precursors were cultured with recombinant mouse granulocyte-macrophage colony-stimulating factor (rmGM-CSF) and interleukin-4 (rmIL-4) to produce immature DCs. Immature DCs were stimulated by LPS 18 h before the end of culture to become mature. DCs' phenotype was detected by flow cytometry (FCM). RelB expression and protein level were determined by RT-PCR and immunofluorescence staining. RESULTS: The expression level of co-stimulatory molecules (CD86 and CD40) and MHC-II class molecule were low in immature DCs, whereas high in mature DCs. RelB expression was significantly higher in mature DCs than in immature DCs (P<0.01). CONCLUSION: RelB expression is closely associated with the maturative situation of DCs. Inhibition of RelB expression in DCs may induce tolerogenic DCs.

Actins↗
PubMed2006

[Effects and prognostic factors of HLA-matched sibling donor allogeneic hematopoietic stem cell transplantation for chronic myelogenous leukemia].

OBJECTIVE: To retrospectively analyze the curative effects and prognostic factors of HLA-matched sibling donor allogeneic hematopoietic stem cell transplantation (allo-HSCT) for chronic myelogenous leukemia patients (CML). METHODS: Of the 35 CML patients, 26 were males and 9 were females, with a median age of 32 (12 - 50) years. 30 patients were in chronic phase of CML, 5 patients were in accelerated phase. Allo-HSCT from HLA identical siblings was performed for 35 patients, of whom 11 received bone marrow transplantation (BMT) and 24 peripheral blood stem cell transplantation (PBSCT). Conditioning regimens was TBI (total-body irradiation) + CY (CTX) protocol in 8 patients and BU/CY protocol in 27 patients. The average follow-up was 48 months (range 7 - 108 months). RESULTS: 34 (97.1%) patients were successfully engrafted. Among them, 21 patients (60.0%) had three years disease-free (DFS) survival. The overall 5-year survival (OS) was 57.1%. Two patients (5.7%) relapsed. Transplant-related mortality occurred in 12 patients. Hemorrhagic cystitis (HC) occurred in 5 patients and HVOD was observed in 1 patient. Acute graft-versus-host disease (aGVHD) occurred in 18 patients (51.4%), among them 7 patients (20.0%) were of grade III-IV. Chronic GVHD was in 17 patients (48.5%). There was no significant difference in 3-years DFS between BMT group and PBSCT group (54.5% vs. 62.5%, P > 0.05). The 3-year disease-free survival (DFS) was 42.9% in TBI/CY group and 55.6% in BU/CY group (P > 0.05). In univariate prognostic analysis model, the DFS at 3 years is 75% and 47.4% for < or =30 years patients and >30 years patients, respectively, P < 0.05. The 3-year DFS of patients with first chronic phase is higher than patients with advanced diseases (61.3% vs. 40%, P < 0. 05). The 3-year DFS in patients of grade I - II GVHD was higher than that in patients of grade III-IV GVHD (81.8% vs. 14.3%, P < 0.05). CONCLUSION: The patients who had transplantation done within 1 year after diagnosis during their first chronic phase of disease and who had low-grade GVHD have better prognosis. Those patients who had III-IV acute GVHD are prone to incorporate severe infection, which was a worse prognostic factor of allo-HSCT for chronic myelogenous leukemia.

Adolescent↗