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Biomedical subjects

Ming Li

Publications and source records attributed to Ming Li.

At least 253 records · Page 14Linked to original sources
PubMed2004

An IL-12-independent role for CD40-CD154 in mediating effector responses: studies in cell-mediated glomerulonephritis and dermal delayed-type hypersensitivity.

Crescentic glomerulonephritis (GN) results from IL-12-driven Th1-directed cell-mediated responses (akin to delayed-type hypersensitivity (DTH)) directed against glomerular Ags. CD40-CD154 interactions are critical for IL-12 production and Th1 polarization of immune responses. Crescentic anti-glomerular basement membrane GN was induced in C57BL/6 (wild-type (WT)) mice (sensitized to sheep globulin) by planting this Ag (as sheep anti-mouse glomerular basement membrane globulin) in their glomeruli. Crescentic GN did not develop in CD40(-/-) mice due to significantly reduced nephritogenic Th1 responses. IL-12 was administered to CD40(-/-) mice with GN to dissect interactions between IL-12 and CD40 in inducing nephritogenic immunity and injury. Administration of IL-12 to CD40(-/-) mice restored Th cell IFN-gamma production, and up-regulated intrarenal chemokines and glomerular T cell and macrophage accumulation compared with WT control mice. Despite this, renal macrophages were not activated and renal injury and dermal DTH were not restored. Thus, CD40-directed IL-12 drives Th1 generation and effector cell recruitment but CD40 is required for activation. To test this hypothesis, activated OT-II OVA-specific CD4(+) cells and OVA(323-339)-loaded nonresponsive APCs were transferred into footpads of WT, CD40(-/-), and macrophage-depleted WT mice. WT mice developed significant DTH compared with CD40(-/-) and macrophage-depleted WT mice. This study demonstrated that CD40-induced IL-12 is required for generation of systemic Th1 immunity to nephritogenic Ags, and that IL-12 enhances Th1 effector cell recruitment to peripheral sites of Ag presentation via generation of local chemokines. Effector cell activation, renal DTH-like injury, and dermal DTH require direct Th1 CD154/macrophage CD40 interactions.

Animals↗
PubMed2004

CCR5 promoter human haplogroups associated with HIV-1 disease progression in Thai injection drug users.

BACKGROUND: An evolutionary-based analysis of the CC chemokine receptor 5 gene (CCR5) promoter region has identified nine stable human haplogroups, within which certain haplogroups appear to influence HIV-1 disease progression differentially among Caucasians and African-Americans. OBJECTIVE: To assess the influence of CCR5 haplogroups on HIV-1 disease progression in a Thai population. DESIGN: Haplogroup analysis of HIV-1-seropositive injection drug users (IDU) participating in a prospective cohort study in Bangkok. All were documented seroconverters with a median follow-up time of 3.5 years (range, 0.2-7.0). METHODS: From a cohort of 130 IDU, 106 (81.5%) were genotyped for the CCR2b-64I, CCR5-delta32 and seven CCR5 promoter alleles constituting the CCR5 haplogroups. Survival curves and adjusted Cox proportional hazards models were used to assess the effect of haplogroups on the time from HIV-1 infection until CD4 count < 200 x 10(6) cells/l. RESULTS: The most common CCR5 haplogroups were HHC (61.8%), followed by HHE (15.6%) and HHF*2 (14.6%). HHE was associated with an accelerated CD4 count decline to < 200 x 10(6) cells/l (adjusted relative hazard, 1.88; 95% confidence interval, 1.05-3.36; P = 0.02). CONCLUSIONS: This is the first evidence that the CCR5 haplogroup E speeds the decline of the CD4 cell count and may lead to accelerated disease progression among HIV-infected Thais. These new observations highlight the need for additional studies involving populations in Asia.

Adult↗
PubMed2004

Surgical treatment of portal vein cavernous transformation.

The aim of this study was to explore the treatment of portal cavernous transformation (PVCT). The surgical treatment of 18 patients with PVCT was studied retrospectively. Eight patients underwent mesocaval shunt with artificial grafts, two patients had splenectomy and disconnection, three patients had a central splenorenal shunt, and six patients had a distal splenorenal shunt. There were no deaths or hepatic encephalopathy after operation. Bleeding recurred in two patients (disconnection in one, mesocaval shunt in one). The individualized choice of shunt is ideal for treating PVCT, and the combined procedures of shunt and disconnection are useful. The Rex shunt will be the focus of PVCT surgery in the future.

Adolescent↗
PubMed2004

Biochemical characterization of protein complexes from the Helicobacter pylori protein interaction map: strategies for complex formation and evidence for novel interactions within type IV secretion systems.

We have investigated a large set of interactions from the Helicobacter pylori protein interaction map previously identified by high-throughput yeast two-hybrid (htY2H)-based methods. This study had two aims: i) to validate htY2H as a source of protein-protein interaction complexes for high-throughput biochemical and structural studies of the H. pylori interactome; and ii) to validate biochemically interactions shown by htY2H to involve components of the H. pylori type IV secretion systems. Thus, 17 interactions involving 31 proteins and protein fragments were studied, and a general strategy was designed to produce protein-interacting partners for biochemical and structural characterization. We show that htY2H is a valid source of protein-protein complexes for high-throughput proteome-scale characterization of the H. pylori interactome, because 76% of the interactions tested were confirmed biochemically. Of the interactions involving type IV secretion proteins, three could be confirmed. One interaction is between two components of the type IV secretion apparatus, ComB10 and ComB4, which are VirB10 and VirB4 homologs, respectively. Another interaction is between a type IV component (HP0525, a VirB11 homolog) and a non-type IV secretion protein (HP01451), indicating that proteins other than the core VirB (1-11)-VirD4 proteins may play a role in type IV secretion. Finally, a third interaction was biochemically confirmed between CagA, a virulence factor secreted by the type IV secretion system encoded by the Cag pathogenicity island, and a non-type IV secretion protein, HP0496.

Bacterial Proteins↗
PubMed2004

Helper requirements for generation of effector CTL to islet beta cell antigens.

We have dissected the helper requirements for converting a tolerogenic CD8 T cell response into one capable of causing destruction of the pancreatic islets. Injection of naive OVA-specific CD8 T cells into transgenic mice expressing OVA in the pancreas only resulted in islet destruction when activated CD4 Th cells were coinjected. This requirement for activated CD4 T cell help for induction of primary CD8 T cell-mediated immunity to tissue Ags contrasts recent reports suggesting that help is only important for CTL memory. Our findings show that signaling of CD40 on the dendritic cell presenting to CD8 T cells is important, but not sufficient, for induction of diabetes. Furthermore, once helpers are activated, they need not recognize Ag on the dendritic cells they license. This provides insight into the helper requirements for adoptive transfer immunotherapy of tumors and suggests key points for inhibition of CTL-mediated autoimmunity.

Adoptive Transfer↗
PubMed2004

[Soluble expression of Plasmodium falciparum glutamate dehydrogenase in Escherichia coli, and its purification and identification].

OBJECTIVE: To make soluble expression of Plasmodium falciparum (FCC1/HN) glutamate dehydrogenase (GDH) in Escherichia coli, purification and immunocompetence identification of the recombinant non-fusion GDH. METHODS: The GDH gene was cloned into prokaryotic expression vector pET23 (a) to form recombinant expression vector pET23 (a)/GDH. pET23(a)/GDH was transformed into E. coli BL21 (DE3). Induced by IPTG (isopropyl-beta D-thiogalactoside), GDH was highly expressed in the supernatant after sonication. The soluble recombinant GDH was purified by Source-Q and Source-S chromatography. Enzyme-linked immunosorbent assay and Western blotting were carried out to identify the immunocompetence of the purified product. RESULTS: SDS-PAGE analysis showed that the soluble GDH protein accounted for approximately 15% of the total bacterial protein. By two-step ion-exchange chromatography, the purity of GDH reached more than 90% and the GDH possessed high antigenicity. CONCLUSION: The soluble expression of GDH results in an integral three-dimensional structure epitope with high biological activity.

Animals↗
PubMed2004

A novel missense mutation of the ATP2A2 gene in a Chinese family with Darier's disease.

Darier's disease (DD) is an autosomal dominant skin disorder that is characterized by multiple keratotic papules, focal loss of adhesion and abnormal keratinization. Mutations in the ATP2A2 gene encoding sarco/endoplasmic reticulum calcium pumping ATPase type 2 have been identified as the molecular basis of DD. We report here a three-generation family with DD, and examined ATP2A2 gene mutations in this family by direct sequencing. A novel missense mutation A-->G was identified in exon 12, nucleotide 1704, which leads to the substitution of lysine by arginine at codon 514 (K514R). This study contributes to the database on ATP2A2 in DD, and further illustrates the extensive diversity of mutational events that lead to the different phenotypes of DD.

Adenine↗
PubMed2004

[Experiment and study of endothelialization of prostheses with bone marrow CD34+ cells].

OBJECTIVE: To exploration the endothelialization of prostheses with bone marrow CD(34)(+) cells. METHODS: CD(34)(+) cells were isolated from bone marrow of carine by an immune magnetic cell sorting system and induced into endothelial cells with VEGF. Seeding the cells to PTFE prostheses which implanted the abdominal aorta artery (AAA) and inferior vena cava (IVC). RESULTS: The isolated cells from bone marrow were CD(34)(+) by flow cytometer which could differentiate into endothelial cells in vascular endothelial growth factor (VEGF). The endothelial cells were identified by immunostaining and transmission electron microscope. The obliteration rate of the seeding grafts implanting AAA was 0%, the stenosis rate 12.5%; the obliteration rate implanting IVC 12.5%, the stenosis rate 25%. CONCLUSION: CD(34)(+) cells were isolated from bone marrow by an immune magnetic cell sorting system and were able to be induced into endothelial cells with VEGF in vitro. PTFE prostheses seeding CD(34)(+) cells have the ideal endothelialization and patency.

Animals↗
PubMed2004

An assessment of World Health Organization criteria for severe acute respiratory syndrome in patients with cancer.

BACKGROUND: The differential diagnosis of severe acute respiratory syndrome (SARS) in patients with cancer can be challenging. Although diagnostic criteria for SARS have been issued by the World Health Organization (WHO), simple adoption of the established criteria may lead to overdiagnosis in patients with cancer or to an increase in the risk of spreading SARS within cancer hospitals. METHODS: The authors report their experience with the exclusion and quarantine of patients with cancer during the peak of the SARS epidemic in Beijing, China. The patients included 4 males and 7 females with a median age of 66 years (range, 39-73 years). RESULTS: All 11 patients met the WHO diagnostic criteria for probable SARS. Among those 11 patients with probable SARS, only 1 had confirmed SARS; for the other 10 patients, the possibility of SARS infection was ruled out. CONCLUSIONS: Special attention must be paid to patients with cancer who have symptoms similar to those seen in SARS. Although the WHO diagnostic criteria for SARS should be widely accepted, they are not definite or practical in certain populations.

Adult↗
PubMed2004

[Genetic risk factors of prostate cancer in Han nationality population in Northern China and a preliminary study of the reason of racial difference in prevalence of prostate cancer].

OBJECTIVE: To investigate the genetic polymorphisms of the three major susceptibility genes, AR, VDR, and SRD5A2 genes, in the Han nationality population in Northern China with a low risk of prostate cancer (Pca) and the relationship of these polymorphisms to the susceptibility to Pca, and to discuss the possible reason causing racial difference of prevalence of PCa. METHODS: Restriction fragment length polymorphism (RFLP) technique and denaturing high-performance liquid chromatography (DHPLC) were used to detect the polymorphic sites in the DNAs from the peripheral blood samples of 116 patients with PCa and 190 normal male controls, all of Han nationality in Northern China. The distribution frequencies of different polymorphic sites were compared with those of the populations with high risk of prostate cancer. RESULTS: The frequencies of SRD5A2 and VDR genotypes were not significantly different between the Pca patients and the controls (P > 0.05). The frequency of CAG repeat < 22 was significantly higher in the Pca group than in the control group (P < 0.05). Statistical analyses of the AR genotype prevalence showed significant differences between the PCa patients and the controls (P < 0.05). The frequencies of AR, VDR, and SRD5A2 genotypes showed significant difference between the Han population in Northern China and the high-PCa risk populations in Western countries. The frequency of CAG > or = 22 was 80.4% in the Han people in Northern China, significantly higher than that in the US Caucasians (52.1%) and Afro-Americans (25%, both P < 0.001). CONCLUSION: There is a significant association between the AR gene CAG polymorphisms and PCa in the Han nationality population in Northern China. The distributions of the genotypes of AR, SRD5A2 and VDR gene are different among different ethnic population, which may be one of the reasons causing the racial difference in prostate cancer risk.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed2004

Inhibition of protein tyrosine kinase activity disrupts early retinal development.

In the present study, we have investigated the role of tyrosine kinase activity during early retinal development in Xenopus laevis. The protein tyrosine kinase (PTK) inhibitors lavendustin A and genistein were used to determine the possible role of tyrosine kinase activity during retinal development in vivo and in vitro. Application of the inhibitors to early embryonic retina disrupted the pattern of lamination in the developing retina. The plexiform layers were severely disorganized or were no longer apparent, and photoreceptor morphogenesis was disrupted. Immunocytochemical analysis verified the presence of focal adhesions in dissociated retinal neuroepithelial cells isolated from St 25 embryos. Application of the PTK inhibitors blocked focal adhesion assembly in these primary cultured cells. To further investigate the regulation of focal adhesions by PTK activity, we examined the effect of lavendustin A on cultured XR1 glial cells. Lavendustin A produced a dose-dependent decrease in the proportion of XR1 cells displaying focal adhesions. Taken together, these results suggest that tyrosine kinase activity is essential for regulating neuroepithelial cell adhesion, migration and morphogenesis during retinal development. Furthermore, the disruption of retinal development may, in part, be due to the inhibition of integrin-mediated signaling.

Animals↗
PubMed2004

NNC 55-0396 [(1S,2S)-2-(2-(N-[(3-benzimidazol-2-yl)propyl]-N-methylamino)ethyl)-6-fluoro-1,2,3,4-tetrahydro-1-isopropyl-2-naphtyl cyclopropanecarboxylate dihydrochloride]: a new selective inhibitor of T-type calcium channels.

Mibefradil is a Ca2+ channel antagonist that inhibits both T-type and high-voltage-activated Ca2+ channels. We previously showed that block of high-voltage-activated channels by mibefradil occurs through the production of an active metabolite by intracellular hydrolysis. In the present study, we modified the structure of mibefradil to develop a nonhydrolyzable analog, (1S, 2S)-2-(2-(N-[(3-benzimidazol-2-yl)propyl]-N-methylamino)ethyl)-6-fluoro-1,2,3,4-tetrahydro-1-isopropyl-2-naphtyl cyclopropanecarboxylate dihydrochloride (NNC 55-0396), that exerts a selective inhibitory effect on T-type channels. The acute IC(50) of NNC 55-0396 to block recombinant alpha(1)G T-type channels in human embryonic kidney 293 cells was approximately 7 microM, whereas 100 microM NNC 55-0396 had no detectable effect on high-voltage-activated channels in INS-1 cells. NNC 55-0396 did not affect the voltage-dependent activation of T-type Ca2+ currents but changed the slope of the steady-state inactivation curve. Block of T-type Ca2+ current was partially relieved by membrane hyperpolarization and enhanced at a high-stimulus frequency. Washing NNC 55-0396 out of the recording chamber did not reverse the T-type Ca2+ current activity, suggesting that the compound dissolves in or passes through the plasma membrane to exert its effect; however, intracellular perfusion of the compound did not block T-type Ca2+ currents, arguing against a cytoplasmic route of action. After incubating cells from an insulin-secreting cell line (INS-1) with NNC 55-0396 for 20 min, mass spectrometry did not detect the mibefradil metabolite that causes L-type Ca2+ channel inhibition. We conclude that NNC 55-0396, by virtue of its modified structure, does not produce the metabolite that causes inhibition of L-type Ca2+ channels, thus rendering it more selective to T-type Ca2+ channels.

Animals↗
PubMed2004

[Effect of interferon-alpha therapy on the capacity of antigen presenting of peripheral blood dendritic cells from patients with chronic hepatitis B].

OBJECTIVE: To study the effect of interferon -alpha therapy on the capacity of antigen presenting of peripheral blood dendritic cells from patients with chronic hepatitis B (CHB). METHODS: The peripheral blood samples were obtained from 23 patients who were given interferon-alpha therapy just before treatment and after treatment for 4 months, respectively. The peripheral blood mononuclear cells (PBMC) were isolated and cultured, and recombinant human IL-4 and GM-CSF were added to the cultures. After cultured for 7 days, dendritic cells (DC) were harvested and then incubated with HBsAg for 3 hours, then mixed with autogenous PBMC and cocultured for additional 72 hours. Before ending the culiration, 7.4 x 10(4) Bq (3)H-TDR was added to the culture for 12 hours, and then all cells were collected and detected for cpm values. Eight healthy individuals were used as controls. RESULTS: After treatment for 4 months with interferon-alpha, the proliferating level of DC markedly increased in posttreatent group when compared with that in the pretreatment group and the total number of DC proliferation averagely increased 2.8 times in the same culture condition. The capacity of antigen presenting of DC in the pretreatment group markedly decreased compared with that either in posttreatment group or in healthy group, respectively (P < 0.001), and there was no significant difference between the posttreatment group and the healthy group (P > 0.05). Both before and after treatment the capacities of DC antigen presenting in interferon-alpha complete responder group were significantly stronger than those in the nonresponder group (P < 0.01 and P < 0.001). There was no significant difference between the partial responder group and nonresponder one (P > 0.05). CONCLUSION: The results indicate the capacity of antigen presenting of peripheral blood DC from CHB patients is dysfunctional. Interferon-alpha therapy may markedly improve the capacity. The potential of antigen presenting of DC in CHB patients may be closely correlated with the response to interferon-alpha therapy.

Adult↗
PubMed2004

Seven novel mutations of the ADAR gene in Chinese families and sporadic patients with dyschromatosis symmetrica hereditaria (DSH).

Dyschromatosis symmetrica hereditaria (DSH) is an autosomal dominant pigmentary genodermatosis characterized by hyperpigmented and hypopigmented macules of on the extremities and caused by the mutations in the ADAR gene(also called DSRAD) encoding for RNA-specific adenosine deaminase. Here we reported clinical and molecular findings of 6 Chinese multi-generation families and 2 sporadic patients with DSH. We found that the same mutation could lead to different phenotypes even in the same family and we did not establish a clear correlation between genotypes and phenotypes. Seven novel heterozygous mutations of ADAR were identified, which were c.2433_2434delAG (p.T811fs), c.2197G>T (p.E733X), c.3286C>T (p.R1096X), c.2897G>T (p.C966F), c.2797C>T (p.Q933X), c.2375delT (p.L792fs) and c.3203-2A>G respectively. Our data add new variants to the repertoire of ADAR mutations in DSH.

Adenosine Deaminase↗
PubMed2004

Antiviral effect of chinonin against herpes simplex virus.

In order to investigate the antiviral effect of chinonin against Herpes simplex virus (HSV), the encephalitis model in mice and skin infection model in guinea pigs were established by HSV- I and HSV-II infection respectively. Acyclovir was used as the positive reference drug to evaluate the antiviral capacity of chinonin. Chinonin showed an obvious therapeutic effect on encephalitis in mice at doses of 25 and 50 mg/kg. At both dosages, chinonin demonstrated stronger protection than acyclovir (1 and 5 mg/kg) to the infected mice from death. It was also found that chinonin could treat the skin infection in guinea pigs effectively. The therapeutic effect of chinonin was similar to that of acyclovir (5 mg/kg) at 25 mg/kg but obviously better than that at 50 and 75 mg/ kg. In conclusion, chinonin is a potential candidate for the treatment against HSV.

Acyclovir↗
PubMed2004

Expression of immunoglobulin kappa light chain constant region in abnormal human cervical epithelial cells.

Although it is generally believed that, under normal conditions, the only source of immunoglobulin is mature B lymphocytes, we recently found several epithelium-derived carcinoma cell lines also express immunolglobulin-like protein. We extended our study to biopsy samples of human cervical tissues with various epithelial lesions. By in situ hybridization, we only detected a low level of mRNA for the immunoglobulin kappa light chain constant region in epithelia with cervicitis. However, in epithelia with dysplasia and carcinoma, the expression of mRNA for the kappa constant region was markedly increased. There was no significant difference in the level of mRNA for the kappa constant region between epithelial dysplasia and carcinoma. The aberrant expression of immunoglobulin kappa light chain constant region in dysplastic and cancerous cervical epithelial cells may serve as a marker for malignant cell transformation.

Base Sequence↗
PubMed2004

Endoluminal and surgical treatment for the management of Stanford Type A aortic dissection.

Stanford Type A aortic dissection is a life-threatening disease. A 46-year-old female patient with Stanford Type A aortic dissection was successfully treated by placing a stent-graft into the ascending aorta via femoral artery. No complication was found immediately after the operation. Bentall operation was performed to treat the development of severe aortic insufficiency 21 months after the stent-grafting procedure. Literature review was done to discuss the possibility of using endoluminal stent placement to treat Stanford Type A aortic dissection.

Aortic Dissection↗