Biomedical subjects

Wei Jin

Publications and source records attributed to Wei Jin.

At least 55 records · Page 3Linked to original sources

PubMed2004

Micro construction of poly(epsilon-caprolactone)/poly(L-lactic acid) blend film by solution casting under microwave irradiation.

The micro construction of poly(epsilon-caprolactone) (PCL) and poly(L-lactic acid) (PLLA) blend films fabricated by solution casting under microwave irradiation was investigated by selective enzymatic degradation and scanning electron microscopy (SEM). The results were totally different from the blends obtained by conventional methods. The blend was more homogeneous and the PCL continuous phase more compact as no spherulites and tiny zone separation were observed from the film surface and no PCL network was observed inside the film, and the degradation of a PCL plank by Pseudomonas lipase was significantly retarded. The distributed PLLA micro spheres were enlarged and amorphous. The thermal behavior of the blend by microwave heating revealed that PCL and PLLA underwent a melting process, which induced the variations of the PCL phase and PLLA spheres. The weight loss caused by degradation of the PCL/PLLA blend obtained by conventional methods (B50c) is greater than that of the blend obtained by microwave methods (B50m), which reflects the change in morphology from a loose PCL network (B50c) to a dense PCL plank (B50m).

Biodegradation, Environmental↗

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

Low-coherence Michelson interferometric fiber-optic multiplexed strain sensor array: a minimum configuration.

A minimum configuration Michelson fiber-optic low-coherence interferometric quasi-distributed sensing system is proposed that permits absolute length measurement in remote reflective sensor arrays. The sensor's reflective signal characteristics have been analyzed, and the relationship between intensities of light and number of sensors is given for evaluation of multiplexing potential. The proposed sensing scheme will be useful for the measurement of strain distribution. An important application may be strain monitoring in smart structures. Experimentally, four-sensor array has been demonstrated.

Journal Article↗

PubMed2004

Catheterization-associated complications of intraperitoneal chemotherapy in advanced gastric cancer.

AIM: To assess the catheterization-associated complications during intraperitoneal chemotherapy (IPCT) for advanced gastric cancer. METHODS: From 1998 to 2002, 80 patients with advanced gastric cancer received a total of 320 courses of IPCT using a large bore central venous catheter and associated complications were analyzed. RESULTS: Catheterization-associated complications occurred in 11 of the 80 patients (13.8%), including abdominal pain caused by catheter in 2 cases (0.63%), insertion failure in 2 cases (0.63%), bowel perforation in 1 case (0.31%) and abdominal pain during chemotherapy in 6 cases (1.88%). No serious complications required surgical intervention. CONCLUSION: IPCT using central venous catheters can be performed safely and simply without severe associated complications.

Adult↗

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

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↗

PubMed2004

Cloning and characterization of a splice variant of human Bardet-Biedl syndrome 4 gene (BBS4).

Bardet-Biedl syndrome (BBS) is a heterogeneous multisystemic disorder characterized primarily by five cardinal features of retinal degeneration, obesity, polydactyly, hypogenitalism and mental retardation. To date, six distinct BBS loci that have been identified on different chromosomes. BBS4 gene is mapped to 15q22.2-23, which when mutated can cause BBS4. Its protein shows strong homology to O-linked N-acetylglucosamine (O-GlcNAc) transferase. Here we report a splice variant of BBS4, which is 2556 bp in length and has an open reading frame coding a predicted 527 amino-acids protein. RT-PCR shows that the cDNA is widely expressed while it has higher expression levels in pancreas, liver and prostate.

Alternative Splicing↗

PubMed2004

Association between single nucleotide polymorphisms in deoxycytidine kinase and treatment response among acute myeloid leukaemia patients.

Development of resistance to 1-beta-arabinofuranosylcytosine (AraC) is a major obstacle in the treatment of patients with acute myeloid leukaemia (AML). Deficiency of functional deoxycytidine kinase (dCK) plays an important role in AraC resistance in vitro. We screened 5378 bp sequences of the dCK gene, including all exons and the 5' flanking region, and identified two single nucleotide polymorphisms (SNPs) in the regulatory region (rSNPs) with high allele frequencies. These two rSNPs (-201C>T and -360C>G) formed two major haplotypes. Genotyping with sequencing and MassARRAY system among 122 AML patients showed that those with -360CG/-201CT and -360GG/-201TT compound genotypes (n = 41) displayed a favourable response to chemotherapy whereas those with -360CC/-201CC (n = 81) tended to have a poor response (P = 0.025). Moreover, real-time quantitative reverse transcriptase-polymerase chain reaction showed that patients with -360CG/-201CT and -360GG/-201TT genotypes expressed higher level of dCK mRNA compared to those with the -360CC/-201CC genotype (P = 0.0034). Luciferase-reporter assay showed that dCK 5' regulatory region bearing -360G/-201T genotype alone had an eight-fold greater transcriptional activation activity compared to that with -360C/-201C genotype, whereas co-transfection of both -360G/-201T and -360C/-201C constructs mimicked the heterozygous genotype, which exhibited a four-fold greater activity compared to that with -360C/-201C. These results indicate that rSNP haplotypes of dCK gene may serve as a genetic marker for predicting drug responsiveness, which will be beneficial in establishing more effective AML chemotherapeutic regimens.

Acute Disease↗

PubMed2004

IkappaB kinase is an essential component of the Tpl2 signaling pathway.

IkappaB kinase (IKK), a key regulator of immune and inflammatory responses, is known as an effector kinase mediating activation of the transcription factor NF-kappaB. Whether IKK also participates in other signaling events is not known. Here we show that IKK serves as an essential component of a signaling pathway that involves activation of the Tpl2 kinase and its downstream targets, MEK1 and ERK. Inhibition of IKKbeta in macrophages eliminates Tpl2 activation and ERK phosphorylation induced by lipopolysaccharide and tumor necrosis factor alpha. Using IKK-deficient murine fibroblasts, we further demonstrate that IKKbeta, but not IKKalpha, is required for Tpl2 activation. Moreover, this novel function of IKKbeta appears to involve phosphorylation and degradation of the Tpl2 inhibitor NF-kappaB1/p105. These findings suggest that IKKbeta exerts its immune-regulatory functions by targeting different downstream signaling pathways.

Animals↗

PubMed2004

Expression of the splicing regulator polypyrimidine tract-binding protein in normal and neoplastic brain.

Polypyrimidine tract-binding protein (PTB) is a nuclear factor that binds to the polypyrimidine tract of pre-mRNA introns, where it is associated with negative regulation of RNA splicing and with exon silencing. We have previously demonstrated that PTB expression is increased during glial cell transformation and that this increase correlates brain and in glial and neuronal tumors. Paraffin sections were stained by using a primary monoclonal antibody against PTB. Tissues that were analyzed included normal with changes in the RNA splicing of the fibroblast growth factor receptor 1. In this paper we examine the specific cellular distribution of PTB expression in normal brain (n = 2) and tumors of various types (low-grade astrocytoma, n = 2; anaplastic astrocytoma, n = 2; glioblastoma, n = 4; medulloblastoma, n = 4; central neurocytoma, n = 2; dysplastic gangliocytoma, n = 1; ganglioglioma, n = 1; paraganglioma, n = 1). In glial cell populations the majority of astrocytes and oligodendrocytes were negative, but occasional positively staining cells were observed. Strongly positive PTB staining was observed in ependymocytes, choroid plexus epithelium, microglia, arachnoid membrane, and adenohypophysis, and weak staining was found in the neurohypophysis. In all cases vascular endothelium and smooth muscle stained strongly. In tumor samples, intense positive nuclear staining was observed in transformed cells of low-grade astrocytoma, anaplastic astrocytoma, glioblastoma multiforme, medulloblastoma, paraganglioma, and the glial population of both ganglioglioma and dysplastic gangliocytoma (the neuronal cells of both were negative). In medulloblastoma, neoplastic neuronal cells were positive, as were other cell lineages. In normal brain, all neuron populations and pineocytes were negative for PTB. We conclude that although glial cells show derepression of PTB expression, a similar mechanism is absent in both nonneoplastic neurons and in most neuronally derived tumor cells. Strong upregulation of PTB expression in tumor cells of glial or primitive neuroectodermal origin suggests involvement of this protein in cellular transformation. Whether PTB affects splicing of RNAs critical to cellular transformation or proliferation is an important question for future research.

Brain↗

PubMed2004

A rare polymorphism of the COX7B2 gene in a Cantonese family with nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is the most common head and neck cancer in southern China, and the genetic susceptibility is believed to play an important role in the aetiology of this malignancy. In our previous studies, one candidate susceptibility locus has been mapped to chromosome 4p11-p14 in a subset of NPC families. In the present study, we screened the cytochrome oxidase VIIb2 (COX7B2) gene which resides in this region and investigated the relationship of single nucleotide polymorphisms (SNPs) of this gene with these familial NPC patients. We identified five novel SNPs in this gene, among them -158101G > T and -157322G > A in promoter region, -109602A > G in intron 2, 78T > A in exon 3, and 354T > A in 3'-untranslational region. The change 78T > A at codon 26 which leads to CAT26CAA (His26Gln) was shared by patients from family 31 that carried the susceptibility haplotype, but not found in cases from other NPC families nor in sporadic cases. However, the frequency of allele A was relatively low in normal controls both from Guangdong and eastern China (0.45% and 0.26%, respectively), and this variant was not found in pooled DNA samples from the white and the black population. Protein sequence alignment showed that the 26His of COX7B2 protein is consistent among different species. Our results suggested that the codon 26 of COX7B2 gene might be conservative during the process of evolution, and the rare variation His26Gln was probably associated with the high risk in NPC pedigree 31.

3' Untranslated Regions↗

PubMed2004

[Induction of differentiation of CD34+ cells in vitro and application in endothelialization of blood vessel prostheses].

OBJECTIVE: To induce differentiation of CD(34)+ cells from varying sources into epithelial cells for potential application of blood vessel prostheses. METHODS: CD(34)+ cells were isolated from canine peripheral blood and bone marrow or human umbilical cord blood by an immune magnetic cell sorting system. The isolated CD(34)+ cells were induced to differentiate into endothelial cells in a liquid culture with VEGF. Endothelial cells were evaluated by immunocytochemistry and transmission electron microscopy. CD(34)+ cells were seeded on PTFE prostheses, which were harvested and observed by electron microscopy. RESULTS: The average isolated CD(34)+ cells from peripheral blood, bone marrow and umbilical cord blood were (26.30+/-2.42)%,(41.84 +/-3.65)%and (74.62+/-4.46)%, respectively. The number of CD(34)+ cells increased with the culture duration and reached to the highest level at the 14th d. Immunostaining showed positive signal for CD31 in endothelial cells and positive for factor VIII in cell culture. Transmission electron microscopy found Weibel-Palade bodies in the cytoplasm. Scanning electron microscopy demonstrated a single- layer of flat cells in the innermost layer of PTFE prostheses, and the cells were not of tropism. CONCLUSION: CD(34)+ cells isolated from peripheral blood, bone marrow and umbilical cord blood can be induced into endothelial cells; bone marrow and umbilical cord blood can be used as the sources of seeding cells for endothelialization of prostheses.

Antigens, CD34↗

PubMed2004

Identification of genes responsive to apoptosis in HL-60 cells.

AIM: To identify genes responsive to apoptosis in HL-60 cells treated by homoharringtonine. METHODS: cDNA microarray technology was used to detect gene expression and the result of microarrays for genes (TIEG and VDUP1) was confirmed by Northern analysis. RESULTS: Seventy-five individual mRNAs whose mass changed significantly were identified. Among these genes (25 were up-regulated and 50 were down-regulated), most are known related to oncogenes and tumor suppressor. Some genes were involved in apoptosis signaling pathways. CONCLUSION: TGF beta and TNF apoptosis signaling pathways were initiated during apoptosis in HL-60 cells. TIEG and VDUP1 play important roles in mediating apoptosis.

Antineoplastic Agents, Phytogenic↗

PubMed2004

[Relationship between six single nucleotide polymorphisms of angiotensinogen gene and essential hypertension].

OBJECTIVE: To evaluate the relationship of six single nucleotide polymorphisms(SNPs) and their haplotypes of angiotensinogen(AGT) gene to essential hypertension(EH) in Chinese Han population. METHODS: The genotypes in 185 patients with EH and 185 healthy controls were determined by the method of ABI PRISM SNaPshot Multiplex Kit using six AGT gene polymorphisms at position -217(G/A), -152(G/A), -20(A/C) and -6(G/A) in the promoter region and T174M, M235T in exon 2. RESULTS: The distribution of AGT genotypes and alleles frequencies showed no significant difference between the group of EH and group of controls (P>0.05). However, haplotype analysis revealed that H4 haplotype frequency, which included -152A, -20C, -6A and 235T alleles, was significantly increased in the group of EH (P<0.05). CONCLUSION: G-152A, A-20C, G-6A and M235T polymorphisms of AGT gene might play an important role in the occurrence of EH in Chinese Han population.

Adult↗

PubMed2004

[Apoptosis and modulatory mechanism of human AHH-1 T lymphocytes induced by gamma-irradiation].

AIM: To explore the apoptotic characteristics and modulatory mechanism of human AHH-1 T lymphoblast induced by ionizing radiation and provide an experimental basis for preventing and treating immune damage in acute radiation sickness. METHODS: TdT-mediated dUTP nick end labeling (TUNEL) and May-Grunwald Giemsa (MGG) staining, MTT colorimetry and immunohistochemical staining were used to detect the T lymphocyte apoptosis, cell survival and the expressions of Bax, Bcl-XL and caspase-3 proteins. RESULTS: (1) Over a definite dose range, apoptotic rate of AHH-1T lymphocytes increased with the elevation of radiation doses, while the lymphocytic survival rate decreased sharply, both showing a good dose-effect relationship. (2) The expression of apoptosis-accelerating protein Bax enhanced obviously with the increase of radiation doses, while apoptosis-inhibiting protein Bcl-XL trended to persistent decline. (3)The activity of activated apoptosis-executing protein caspase-3 heightened significantly with increased radiation doses, which revealed a better corresponding relationship to apoptotic rate. CONCLUSION: A great number of apoptotic AHH-1 T cells may be one of major accounts for the lymphocyte rapid reduction and depressed organism immune function induced by irradiation. Bax, Bcl-XL and caspase-3 proteins play an important role in the regulation of radiation-induced T cell apoptosis.

Apoptosis↗

PubMed2004

[Reversal of resistance to adriamycin in human breast cancer cell line MCF-7/ADM by beta-elemene].

OBJECTIVE: To study the reversal mechanism of adriamycin (ADM) resistance in human breast cancer cell line MCF-7/ADM by beta-elemene (beta-ELE), a wide spectrum anticancer drug derived from the Chinese herb Curcuma chaeocaulis. METHODS: Sensitivity to ADM of MCF-7/ADM cells was studied by MTT assay. Intracellular accumulation of ADM in MCF-7/ADM cells was observed by fluorescent-spectrophotometry. Expression of bcl-2 protein was detected by flow cytometry. RESULTS: A non-cytotoxic dose (6 micro g/ml) and a weakly cytotoxic dose (13 micro g/ml) of beta-ELE could significantly enhance the cytotoxic effects of ADM on MCF-7/ADM cells to 1.4 and 2.2 fold as compared to the beta-ELE untreated control cells. The intracellular concentration of ADM in MCF-7/ADM cells was significantly increased after treatment with beta-ELE (P < 0.01). The expression of bcl-2 protein in MCF-7/ADM cells was reduced from 90.2% to 70.0% (P < 0.05). CONCLUSION: beta-ELE could partially reverse the drug resistance to ADM in MCF-7/ADM, which is related to the increased accumulation of intracellular ADM and the decreased expression of bcl-2.

Antineoplastic Agents, Phytogenic↗

PubMed2004

[Semen analysis of DNA fluorescence detection and two other routine analyzing methods].

OBJECTIVE: To compare semen analysis system of computer-aided sperm analysis (CASA) dyeing with DNA fluorescence (simplified as fluorescence CASA) with two other routine semen analyzing methods. METHODS: Twenty-two male infertile patients were selected at random as research subjects, and semen analysis was performed with fluorescence CASA, grey CASA, and microscopic analysis. RESULTS: Fluorescence CASA could distinguish sperm from non-sperm granules, as well as living from dead sperm. Compared with the sperm density detected by fluorescence CASA, the disparities of sperm densities detected by microscopic analysis and grey CASA were (9.23 +/- 8.01) x 10(6)/ml and (10.27 +/- 6.22) x 10(6)/ml, and the disparity rates of sperm density were 49.06% +/- 49.87% and 43.39% +/- 25.56% respectively. CONCLUSION: Fluorescence CASA was more conformable to the requirements of latest WHO laboratory manual for the examination of human semen, and worth recommending for the clinical analysis of semen features, especially sperm density.

Adult↗

PubMed2004

[The effects of acute large dose of gamma-irradiation on immune function of mice].

AIM: To observe the effects of large dose of gamma-irradiation on immune function of mice. METHODS: 225 cleaning-grad C57 mice, weighing(20+/-2.0) g, were randomly divided into 6 groups, and treated with 0, 6, 9, 12, 15 and 20 Gy gamma-irradiation. At different times after irradiation, lymphocytes were collected and lymphocytic apoptosis and T cell subsets were analyzed by TUNEL, May-Grunwald Giemsa (MGG) staining and flow cytometry. RESULTS: (1)At early stage(1-14) d after radiation, the apoptotic rate of peripheral blood lymphocytes increased significantly and 12 Gy radiation resulted in the highest apoptotic rate. The number of T lymphocytes and T cell subsets decreased continuously in a dose-dependent manner. CD8(+) T cells were the most sensitive in T cell subsets to irradiation. These results suggested that early severe injury might be one of the important features of immune injury caused by acute radiation. (2) One month after radiation, the apoptotic rate of lymphocytes began to decrease and T lymphocytes and their subsets recovered gradually. However, neither the lymphocytic apoptotic rate nor the number of CD3(+) T cells and CD8(+) T cells, recovered to normal level, indicating that large dose of radiation had severe remote effects on immune function. CONCLUSION: Apoptosis of a large number of peripheral blood lymphocytes in early stage after radiation may result in sharp reduction of T cell number and late immune function depression.

Animals↗