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Biomedical subjects

Yuan Li

Publications and source records attributed to Yuan Li.

At least 199 records · Page 11Linked to original sources
PubMed2002

Morphine enhances HIV infection of human blood mononuclear phagocytes through modulation of beta-chemokines and CCR5 receptor.

BACKGROUND: Injection drug use remains a significant risk for acquiring HIV infection. The mechanisms by which morphine enhances HIV infection of human immune cells are largely unknown. OBJECTIVE: In this study, we sought to determine the possible mechanisms by which morphine upregulates HIV infection of human blood monocyte-derived macrophages (MDM). METHODS: In this study, MDM were infected with the R5, X4, and R5X4 HIV strains. HIV replication was determined by performing reverse transcriptase activity assays. HIV receptors were determined by performing reverse transcriptase polymerase chain reactions and flow cytometry assays. beta-chemokines were analyzed by performing enzyme-linked immunosorbent assays. In addition, HIV R5 strain and murine leukemia virus envelope-pseudotyped HIV infection was performed to determine whether morphine affects HIV infection of macrophages at entry level. RESULTS: Morphine significantly enhanced HIV R5 strain infection of MDM but had little effect on X4 strain infection. The macrophage-tropic R5 strain envelope-pseudotyped HIV infection was markedly increased by morphine, whereas murine leukemia virus envelope-pseudotyped HIV infection was not significantly affected. Furthermore, morphine significantly upregulated CCR5 receptor expression and inhibited the endogenous production of beta-chemokines in MDM. The opioid receptor antagonist naltrexone blocked the effects of morphine on the production of beta-chemokines. CONCLUSION: Opiates enhance HIV R5 strain infection of macrophages through the downregulation of beta-chemokine production and upregulation of CCR5 receptor expression and may have an important role in HIV immunopathogenesis.

Chemokines, CC↗
PubMed2002

[Gene cloning and expression of CTLA-4 in Streptomyces lividans].

Gene cloning and expression of CTLA-4 was performed in S. lividans with two new types of different signal peptides--vsi and gpp to investigate the secretory expression efficiency of CTLA-4. The hsCTLA-4 gene was fused to the vsi sequences and then inserted into the shuttle vector-pUWL-219. At the same time, the hsCTLA-4 was inserted into the downstream of gpp signal peptide in the plasmid pLNSP. Then the recombinant plasmids were transformed into S. lividans TK24 respectively. The two engineering strains were named as S. lividans [pUWL219-VC] and S. lividans [pLNSP/CTLA-4]. The result of SDS-PAGE and Western blotting show that the recombinant strain S. lividans [pUWL219-VC] and S. lividans [pLNSP/CTLA-4] can express CTLA-4 with about MW 13,000 which is similar to those reported earlier and have immunoactivity. It is the first time that CTLA-4 expression in S. lividans is reported.

Abatacept↗
PubMed2002

[Proliferating activity and differentiation between peripheral cells and central cells in ameloblastoma].

OBJECTIVE: To investigate the proliferating activities and differentiation between peripheral cells and central cells in ameloblastoma. METHODS: Expressions of proliferating cell nuclear antigen (PCNA), Ki-67, CK10&13 and CK19 were detected in 43 ameloblastoma (15 follicular, 20 plexiform and 8 acanthomatous) by SP immunohistochemical methods. RESULTS: The PCNA labelling indices were significantly higher in peripheral cells (5.12% +/- 2.76%) of tumour nests or strands than in central cells (1.36% +/- 1.02%, P < 0.001). The peripheral cells of tumour nests or strands exhibited a significantly higher Ki-67 labelling index (3.63% +/- 1.80%) than central cells (1.26% +/- 0.96%, P < 0.001). The labelling indices between PCNA and Ki-67 showed a significant correlation (P < 0.01). The positive expressions of CK10&13 and CK19 were significantly higher in central cells than in peripheral cells (P < 0.01). CONCLUSIONS: The peripheral zones of tumour nests or strands are regarded as proliferating areas; there exists a significantly different differentiation between central cells and peripheral cells.

Adolescent↗
PubMed2002

[Expression of the human soluble low density lipoprotein receptor in methylotropic yeast].

To obtain the expression of human low density lipoprotein receptor ligand binding domain in methylotropic yeast, firstly the DNA fragment encoding for human low density lipoprotein receptor ligand binding domain was amplified by RT-PCR with human hepatoma Bel-7402 total RNA as template. The nucleotide sequencing analysis indicated that the sequence of the cloned DNA fragment was as same as the reported human LDLR cDNA sequence. Then the expression vector pPIC9K-sLDLr was constructed, linearized and introduced into Pichia pastoris GS115 by electroporation. The recombinant sLDLR was identified by SDS-PAGE, Western blot and Ligand binding blot in supernatant of GS115/pPIC9K-sLDLr. The SDS-PAGE and Western blot analysis showed that the apparent molecular weight of expressed sLDLR was about 36 kD. And the ligand binding blot analysis indicated the expressed sLDLR has the biological activity. The sLDLR, which had the biological activity, was successfully secretorily expressed in the Pichia pastoris (GS115).

Binding Sites↗
PubMed2002

Value of four-chamber view of the fetal echocardiography for the prenatal diagnosis of congenital heart dise.

OBJECTIVE: To investigate the value of four-chamber view for the prenatal diagnosis of congenital heart disease. METHODS: A total of 780 fetal hearts were examined by the four-chamber view between 16 and 36 weeks of gestation, and the clinical data were analyzed and the newborns were followed. RESULTS: Among the 780 fetus, the four-chamber view was obtained in 94.6% of the fetus and three of them were found abnormal and heart malformations were diagnosed. One was Ebstein syndrome, the second was seriously ventricular septal defect and the third was single ventricle and single atrium. The first and the third case were confirmed after birth by echocardiography and autopsy, and the second case was single ventricle and single atrium diagnosed by echocardiography of the newborn. The other 777 newborns were followed to six weeks after birth. Three more heart malformations were diagnosed. One is ventricular septal defect, one is atrial septal defect and the third is pulmonary artery stenosis with atrial septal defect. The sensitivity of the four-chamber view for the prenatal diagnosis of the congenital heart disease is 50% and the specificity is 100%. CONCLUSIONS: The four-chamber view of fetal heart shows the majority structures of the fetal heart and the successive rate of detection is high. It has a higher sensitivity and a very high specificity for the identification of congenital heart disease. We advocate the four-chamber view of fetal heart as a basic obstetric scanning.

Echocardiography↗
PubMed2002

Concentration, distribution and expression of interleukin-5 in human nasal polyp tissues.

OBJECTIVES: To study the concentration, distribution and expression of IL-5 in nasal polyp tissues and explore its significance in micro-environment differentiation of eosinophil accumulation. METHODS: The concentration and expression of IL-5 in nasal polyp tissues of 40 patients were determined by ELISA and immunohistochemistry and inferior turbinate mucosa from patients with nasal polyps and healthy volunteers were used as control. RESULTS: IL-5 concentration in polyp tissues was significantly higher than that in turbinate mucosa (P < 0.05). There was no significant difference in the turbinate mucosae between patients with nasal polyps and healthy volunteers (P > 0.05). IL-5 concentrations in polyp tissues were markedly higher in patients with allergic rhinitis compared with those without (P < 0.05). IL-5 concentrations had no correlation with age and sex (P > 0.05). 80.1% of the eosinophils were positive for IL-5 and 90.9% of IL-5 positive cells were eosinophils. Only 3.7% of lymphocytes and neutrophils were positive for IL-5; IL-5 was not detectable in epithelial cells. IL-5 expression in eosinophils of polyp tissues was remarkably stronger than that of the turbinate mucosa (P < 0.05); there was no significant difference in the the turbinate mucosae between patients with nasal polyps and healthy volunteers (P > 0.05). IL-5 expression of eosinophils in polyp tissue was significantly stronger in patients with allergic rhinitis compared with those without (P < 0.05). There was no significant difference in IL-5 expression in lymphocytes and neutrophils between polyp tissues and turbinate nasal mucosa (both P > 0.05). CONCLUSION: IL-5 is the key cytokine in eosinophilic pathologic mechanisms in nasal polyp tissues.

Adult↗
PubMed2002

[Cloning and expression of VEGF receptor Flt-1 gene in S. lividans TK24].

Using RNA extracted from human umbilical vein endothelium cell as a template, the gene VEGF receptor Flt-1 was amplified by RT-PCR. Recombinant plasmid pSGLgpp-F was constructed and was transformed into S. lividans TK24. With the detection of SDS-PAGE and Western blot, a specific band being same to the reports near 63.6 kd was found. The results showed sFlt-1 was successfully expressed in S. lividans. The result of the binding assay of receptor-ligand for sFlt-1 showed sFlt-1 has the biological activity of binding with its ligand VEGF.

Cloning, Molecular↗
PubMed2002

[Effect of erythromycin on apoptosis of eosinophils in nasal polyps in vitro].

OBJECTIVE: To study the effect of erythromycin on apoptosis of eosinophils in nasal polyps in vitro. METHODS: Fifteen nasal polyp biopsies were collected during nasal polypectomy. The specimens were cultured with erythromycin in RPMI1640, and cultured without erythromycin as control group. The explants in both groups were taken out at 1, 3, 5 day after culture. The apoptosis of cells was detected by terminal deoxynucleotidyl transferasemediated dUTP nick endlabeling(TUNEL), eosinophils were identified by morphology and serial sections stained with HE, then the apoptosis index (AI) of eosinophils was calculated. RESULTS: The AI of eosinophils in nasal polyps after cultured for 1,3,5 days with erythromycin were (31.77 +/- 9.52)%, (32.67 +/- 9.44)% and (50.34 +/- 8.78)% respectively. In control group, the AI of eosinophils were (29.18 +/- 7.31)%, (29.82 +/- 12.03)% and (42.25 +/- 8.08)% respectively. There were significant difference between two groups at 5 day after culture(P < 0.05). CONCLUSION: Erythromycin promoted apoptosis of eosinophils in nasal polyps in vitro.

Adolescent↗
PubMed2002

[Traumatic optic neuropathy: importance and result of surgical treatment].

OBJECTIVE: To explore the importance and result of surgical treatment in traumatic optic neuropathy (TON). METHODS: The results of optic canal and orbital apex decompression by the endonasal endoscopic approach were analyzed in 52 cases (53 eyes), follow up 6 months to 3 years. RESULTS: Twenty one eyes (39.6%) consisting of 14 eyes without effect by corticosteroids treatment(14/37, 37.8%) and 7 eyes with single surgery(7/16, 43.8%) showed improved vision after surgery. 18 eyes with no light perception (18/49, 36.7%) and 3 eyes with poor sight (3/4, 75.0%) had improved vision after surgery. CONCLUSION: The surgical treatment is important for elevating curative effect of TON.

Adolescent↗
PubMed2002

[Expression of P-selectin in nasal polyps and its mechanisms].

OBJECTIVE: To investigate the expression of P-selectin and its mechanism in nasal polyps. METHODS: The expression of P-selectin was detected with immunohistochemistry and reverse transcriptase polymerase chain reaction (RT-PCR) in nasal polyps from 24 patients and nasal epithelium from 9 normals. The production of P-selectin in supernatans of isolated cultured vascular endothelial cells induced by interleukin-5 (IL-5) was detected with enzyme-linked immunosorbent assay (ELISA). RESULTS: The positive rate of P-selectin in nasal polyps was 79.1% (19/24) while it was 22.2%(2/9) in normals. The relative density ratio of P-selectin and beta-actin were 0.68 +/- 0.11 in nasal polyps and 0.29 +/- 0.08 in normals indicated by RT-PCR and agrose electrophoresis. The concentration of P-selectin was (53.4 +/- 2.9) ng/L and (21.3 +/- 3.5) ng/L in the two groups respectively. CONCLUSIONS: P-selectin upregulated in nasal polyps correlated with the infiltrated eosinophils and IL-5 could induce the expression of P-selectin protein in the isolated cultured endothelial cells. It suggested that upregulation of P-selectin may play a role in the pathogenesis of nasal polyps and can be enhanced by cytokine IL-5.

Adolescent↗
PubMed2002

[Orbital surgery by transnasal endoscopic ethmoidal-lamina papyracea approach].

OBJECTIVE: To explore the feasibility of transnasal endoscopic surgery to treat some kinds of diseases within orbit by ethmoidal-lamina papyracea approach, and put forward the basic principle of surgical management. METHODS: A total of 10 cases undergone the endoorbital operation by transnasal endoscopic ethmoidal-lamina papyracea approach, including foreign body 4 cases, sponge haemangioma 1 case, invaded and metastatic carcinoma 5 cases. RESULTS: Successful removing of foreign body from endoorbital for 3 cases, and 1 failure. One case of sponge haemangioma was removed completely. One case of metastatic tumour from nasopharyngeal carcinoma was resected, with no relapse and vision recovered to 0.6 during follow-up period of 4 years. Four cases of invaded carcinoma from ethmosphenoidal sinus were resected completely. Follow-up for 1-4 years showed no relapse. CONCLUSION: The endoorbital region inside the optic nerve can be controlled by transnasal endoscopic ethmoidal-lamina papyracea approach. The advanced radiotherapy provides favourable conditions for conservative surgery of endoorbital carcinoma.

Adult↗
PubMed2002

[Surgical management of cerebrospinal fluid rhinorrhea].

OBJECTIVE: To summarize the clinical experience in managing cerebrospinal fluid (CSF) rhinorrhea. To ascertain the best effective surgical management for CSF rhinorrhea. METHODS: A retrospective study of 83 patients with CSF rhinorrhea from March 1991 to August 2001 was conducted. Among them, 17 patients were treated with conservative therapy, 8 with transcranial repair, 2 with extranasal repair, 3 with transnasal repair under microscope and 54 with transnasal endoscopic management. The conservative time, causes, complications, leak sites, repairing materials and surgical methods were analysed. RESULTS: All patients were followed -up for 6 months to 9 years. 17 cases had no CSF rhinorrhea after conservative treatment with an average time 16 days. Endoscopic repair of CSF leaks was successful in 90% (49/54) of the cases after a first attempt. Two persistent leaks (2/4) were closed after a second attempt. The other persistent leaks were also closed, one case after third and one after fourth attempt. Ultimately 98% (53/54) of the leaks were repaired using an endoscopic approach. Only one failed after transendoscopic management, and succeeded with a second extranasal repair. The CSF rhinorrhea repaired with other surgical methods were all successful. CONCLUSION: Transnasal endoscopic management is the best method for repairing CSF rhinorrhea, other surgical methods can be chosen based on different conditions. The conservative time are 2 to 4 weeks if a CSF leak is caused by trauma or operation, 6 to 8 weeks conservative time for special cases.

Adolescent↗
PubMed2002

[Exploration of transnasal endoscopic cranialbase approach].

OBJECTIVE: To study feasibility and indication of cranialbase surgery by transnasal endoscopic approach. METHODS: Nine cases treated by transnasal were analysed. Those cases included foreign body, olfactory neuroblastoma, meningoma and inverted papilloma in anterior cranial fossa, sinuses sphenoidalis macrosis cyst invading middle cranial fossa, primary cholesteatoma and space occupying lesion in middle cranial fossa. RESULT: The complications were not occurred in all cases. Follow-up survey 1-7 years, no-relapse was occurred. CONCLUSION: It is probability that surgery lesion be close skull base by transnasal endoscopic approach, but indication must be exactitude selected. The operator should be have firm anatomic, skilled operation and richness experience. The malignancy lesion should be compositive treatment after surgery.

Adolescent↗
PubMed2001

Methadone enhances human immunodeficiency virus infection of human immune cells.

Opiate abuse has been postulated to be a cofactor in the immunopathogenesis of acquired immunodeficiency syndrome (AIDS). This study evaluated whether methadone, a drug widely prescribed for the treatment of drug abusers with opioid dependence, affects human immunodeficiency virus (HIV) infection of human immune cells. When added to human fetal microglia and blood monocyte-derived macrophage cultures, methadone significantly enhanced HIV infection of these cells. This enhancement was associated with the up-regulation of expression of CCR5, a primary coreceptor for macrophage-tropic HIV entry into macrophages. Most importantly, the addition of methadone to the cultures of latently infected peripheral blood mononuclear cells from HIV-infected patients enhanced viral activation and replication. Although the in vivo relevance of these findings remains to be determined, the data underscore the necessity of further studies to define the role of opioids, including methadone, in the immunopathogenesis of HIV infection and AIDS.

Adult↗
PubMedDate not supplied

Drug abuse, innate immunity and hepatitis C virus.

Since its discovery in 1989, hepatitis C virus (HCV) has become a major public health problem. HCV chronically infects an estimated 170 million people worldwide. The seroprevalence of anti-HCV antibody in the United States has been estimated at 1.8%, which corresponds to approximately 4 million people. HCV is the most common chronic blood borne infection in the United States, and the leading cause of liver transplantation in developed countries. Injection drug use is the dominant mode of HCV transmission and accounts for up to 90% of current infections. Opiates and other drug abuse, such as alcohol, have been implicated as cofactors in the pathogenesis of HCV disease. Injection drug use has been the most common risk factor identified in alcoholics with HCV infection. Both opiates and alcohol contribute significantly to morbidity and mortality from HCV disease. These drugs most likely act synergistically to promote the development and progression of HCV disease. However, there is limited information available concerning the interaction of the drug abuse with the host cell innate immunity against HCV infection, which is a major barrier to fundamental understanding of the immunopathogenesis of HCV disease. Therefore, defining the role of the drug abuse in the development of chronic HCV infection is of crucial importance and should provide practical guidance toward the reduction of risk factors that interfere with therapeutic approaches for HCV infection and disease. This review paper focuses on the interplay between drug abuse (opiates and alcohol), innate immunity and HCV in the context of the development of HCV disease.

Alcoholism↗
PubMedDate not supplied

Distribution and characteristics of hematogenous disseminated tuberculosis within the abdomen on contrast-enhanced CT.

BACKGROUND: The incidence of abdominal tuberculous lymphadenopathy never appears low. In addition to infecting the abdominal lymph nodes through the digestive tract, the tuberculosis bacteria can also infect the abdominal lymph nodes and extra-nodal organs through hematogenous dissemination. This study investigated contrast-enhanced CT features and anatomic locations of hematogenous disseminated tuberculosis involving abdominal organs. METHODS: Thirteen patients with documented hematogenous disseminated tuberculosis involving abdominal organs were recruited. Contrast-enhanced CT scanning was carried out in the abdomen of all patients. CT images were retrospectively analyzed for the size, attenuation, enhancement patterns, and anatomic distribution of the foci in infected lymph node, liver, spleen, and kidney. RESULTS: Hematogenous disseminated tuberculosis dominantly affected lymph nodes in the hepatoduodenal ligament (84.6%), the portacaval space (84.6%), the root of the mesentery (84.6%), the peripancreatic region (84.6%), the periceliac region (76.9%), the hepatogastric ligament (69.2%), and the upper and lower paraaortic region (both were 69.2%). Out of the 13 cases studied, 12 (92.3%) had lymphadenopathy with peripheral enhancement accompanied by multilocular appearance; 10 (76.9%) had homogeneous hepatomegaly; 13 (100%) had inhomogeneous splenomegaly accompanied by scattered low-density lesions with peripheral enhancement; and 8 (61.5%) had low-density lesions in the kidney with peripheral enhancement. CONCLUSION: Anatomically, peritoneal and retroperitoneal lymph nodes are most susceptible to hematogenous disseminated tuberculosis. The hepatomegaly manifested to be homogeneous in most cases while the splenomegaly is of frequently inhomogeneous attenuation. All these characteristics are closely related to the infection routes and pathologic features of abdominal hematogenous disseminated tuberculosis.

Abdomen↗