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Biomedical subjects

Min Zhu

Publications and source records attributed to Min Zhu.

At least 91 records · Page 5Linked to original sources
PubMed2003

Multilineage cells from adipose tissue as gene delivery vehicles.

We have characterized a population of mesenchymal progenitor cells from adipose tissue, termed processed lipoaspirate (PLA) cells, which have multilineage potential similar to bone marrow-derived mesenchymal stem cells and are also easily expanded in culture. The primary benefit of using adipose tissue as a source of multilineage progenitor cells is its relative abundance and ease of procurement. We examined the infection of PLA cells with adenoviral, oncoretroviral, and lentiviral vectors. We demonstrate that PLA cells can be transduced with lentiviral vectors at high efficiency. PLA cells maintain transgene expression after differentiation into adipogenic and osteogenic lineages after lentiviral transduction. Therefore, PLA cells and lentiviral vectors may be an efficient combination for use as a therapeutic gene delivery vehicle.

Adenoviridae↗
PubMed2003

Implications of glucose transporter protein type 1 (GLUT1)-haplodeficiency in embryonic stem cells for their survival in response to hypoxic stress.

Glucose transporter protein type 1 (GLUT1) is a major glucose transporter of the fertilized egg and preimplantation embryo. Haploinsufficiency for GLUT1 causes the GLUT1 deficiency syndrome in humans, however the embryo appears unaffected. Therefore, here we produced heterozygous GLUT1 knockout murine embryonic stem cells (GT1+/-) to study the role of GLUT1 deficiency in their growth, glucose metabolism, and survival in response to hypoxic stress. GT1(-/-) cells were determined to be nonviable. Both the GLUT1 and GLUT3 high-affinity, facilitative glucose transporters were expressed in GT1(+/+) and GT1(+/-) embryonic stem cells. GT1(+/-) demonstrated 49 +/- 4% reduction of GLUT1 mRNA. This induced a posttranscriptional, GLUT1 compensatory response resulting in 24 +/- 4% reduction of GLUT1 protein. GLUT3 was unchanged. GLUT8 and GLUT12 were also expressed and unchanged in GT1(+/-). Stimulation of glycolysis by azide inhibition of oxidative phosphorylation was impaired by 44% in GT1(+/-), with impaired up-regulation of GLUT1 protein. Hypoxia for up to 4 hours led to 201% more apoptosis in GT1(+/-) than in GT1(+/+) controls. Caspase-3 activity was 76% higher in GT1(+/-) versus GT1(+/+) at 2 hours. Heterozygous knockout of GLUT1 led to a partial GLUT1 compensatory response protecting nonstressed cells. However, inhibition of oxidative phosphorylation and hypoxia both exposed their increased susceptibility to these stresses.

Animals↗
PubMed2003

Defects in expression of genes related to synaptic vesicle trafficking in frontal cortex of Alzheimer's disease.

Loss of synapses correlates with cognitive decline in Alzheimer's disease (AD). However, molecular mechanisms underlying the synaptic dysfunction and loss are not well understood. In this study, microarray analysis of brain tissues from five AD cases revealed a reduced expression of a group of related genes, all of which are involved in synaptic vesicle (SV) trafficking. By contrast, several synaptic genes with functions other than vesicle trafficking remained unchanged. Quantitative RT-PCR confirmed and expanded the microarray findings. Furthermore, immunoblotting showed that the protein level of at least one of these gene products, dynamin I, correlated with its reduced transcript. Immunhistochemical analysis exhibited an altered distribution of dynamin I immunolabeling in AD neurons. Microarray analysis of transgenic mice with mutated amyloid precursor protein showed that although the transcript levels for some of the SV trafficking-related genes are also decreased, the change in dynamin did not replicate the AD pattern. The results suggest a link among SV vesicle-trafficking pathways, synaptic malfunction, and AD pathogenesis.

Aged↗
PubMed2003

In vitro differentiation of human processed lipoaspirate cells into early neural progenitors.

Human processed lipoaspirate (PLA) cells are multipotent stem cells, capable of differentiating into multiple mesenchymal lineages (bone, cartilage, fat, and muscle). To date, differentiation to nonmesodermal fates has not been reported. This study demonstrates that PLA cells can be induced to differentiate into early neural progenitors, which are of an ectodermal origin. Undifferentiated cultures of human PLA cells expressed markers characteristic of neural cells such as neuron-specific enolase (NSE), vimentin, and neuron-specific nuclear protein (NeuN). After 2 weeks of treatment of PLA cells with isobutylmethylxanthine, indomethacin, and insulin, about 20 to 25 percent of the cells differentiated into cells with typical neural morphologic characteristics, accompanied by increased expression of NSE, vimentin, and the nerve-growth factor receptor trk-A. However, induced PLA cells did not express the mature neuronal marker, MAP, or the mature astrocyte marker, GFAP. It was also found that neurally induced PLA cells displayed a delayed-rectifier type K+ current (an early developmental ion channel) concomitantly with morphologic changes and increased expression of neural-specific markers. The authors concluded that human PLA cells might have the potential to differentiate in vitro into cells that represent early progenitors of neurons and/or glia.

Adult↗
PubMed2003

Comparison of multi-lineage cells from human adipose tissue and bone marrow.

Our laboratory has recently characterized a population of cells from adipose tissue, termed processed lipoaspirate (PLA) cells, which have multi-lineage potential similar to bone-marrow-derived mesenchymal stem cells (MSCs). This study is the first comparison of PLA cells and MSCs isolated from the same patient. No significant differences were observed for yield of adherent stromal cells, growth kinetics, cell senescence, multi-lineage differentiation capacity, and gene transduction efficiency. Adipose tissue is an abundant and easily procured source of PLA cells, which have a potential like MSCs for use in tissue-engineering applications and as gene delivery vehicles.

Adipose Tissue↗
PubMed2003

Increased gene expression of beta-1,4-galactosyltransferase I in rat injured sciatic nerve.

During neurite outgrowth on basal lamina, cell-surface beta-1,4-galactosyltransferase I (beta-1,4-GalT-I) functions as one of the receptors of laminin by binding to N-linked oligosaccharides on the laminin E8 domain. In the present study, it was revealed that in rat injured sciatic nerves, the expression of beta-1,4-GalT-I mRNA reached its peak 2-3 d after axotomy in both proximal and distal stumps, and decreased thereafter as demonstrated by Northern blot analysis. In situ hybridization revealed that beta-1,4-GalT-I mRNAmainly localized in Schwann cells of the injured nerves. Moreover the Galbeta1-4GlcNAc (N-acetylglucosamine) group mainly localized in Schwann cells of the injured nerves by Ricinus communis agglutinin-I (RCA-I) lectin histochemistry. However, the changes in abundance of the Galbeta1-4GlcNAc group in injured nerves were not consistent with the expression of beta-1, 4-GalT-I mRNA. These findings indicate that beta-1,4-GalT-I might be involved in the regeneration of injured peripheral nerves at the early injury stage.

Animals↗
PubMed2003

Interleukin-10 modified dendritic cells induce allo-hyporesponsiveness and prolong small intestine allograft survival.

AIM: To investigate whether IL-10-transduced dendritic cells (DCs) could induce tolerogenicity and prolong allograft survival in rat intestinal transplantation. METHODS: Spleen-derived DCs were prepared and genetically modified by hIL-10 gene. The level of IL-10 expression was quantitated by ELISA. DC function was assessed by MTT in mixed leukocyte reaction. Allogeneic T-cell apoptosis was examined by flow cytometric analysis. Seven days before heterotopic intestinal transplantation, 2 X 10(6) donor-derived IL-10-DC were injected intravenously, then transplantation was performed between SD donor and Wistar recipient. RESULTS: Compared with untransduced DC, IL-10-DC could suppress allogeneic mixed leukocyte reaction (MLR). The inhibitory effect was the most striking with the stimulator/effector (S/E) ratio of 1:10. The inhibition rate was 33.25%, 41.19% (P<0.01) and 22.92% with the S/E ratio of 1:1, 1:10 and 1:50 respectively. At 48 hours and 72 hours by flow cytometry counting, apoptotic T cells responded to IL-10-DC in MLR were 13.8% and 30.1%, while untransduced group did not undergo significant apoptosis (P<0.05). IL-10-DC pretreated recipients had a moderate survival prolongation with a mean allograft survival of 19.8 days (P<0.01), compared with 7.3+/-2.4 days in control group and 8.3+/-2.9 days in untransduced DC group. Rejection occurred in the control group within three days. The difference between untreated DC group and control group was not significant. CONCLUSION: IL-10-DC can induce allogenic T-cell hyporesponsiveness in vitro and apoptosis may be involved in it. IL-10-DC pretreatment can prolong intestinal allograft survival in the recipient.

Animals↗
PubMed2003

SPD-754. Shire.

Shire Pharmaceuticals is developing SPD-754 for the potential treatment of HIV infection. Phase I trials had been completed by October 2002, and phase II trials were initiated in December 2002.

Animals↗
PubMed2003

[Treatment of distraction osteogenesis in the patients of obstructive sleep apnea-hypopnea syndrome with micrognathia].

OBJECTIVE: To apply the treatment of distraction osteogenesis(DO) to obstructive sleep apnea-hypopnea syndrome(OSAHS) patients with croniomaxillofacial deformities. METHODS: All 46 OSAHS patients with micrognathia are had polysomnography(PSG) study and cephalometric analysis. Their age from 4 to 18 years old, the mean age is 11.4. The number of temporal mandibular joint (TMJ) ankylosis with micrognathia, micrognathia; 1st & 2nd bronchial arch syndrome and crouzon syndrome patients were 32, 9, 2 and 3 respectively. All were treated with DO. Maxilla or mandible was advanced from 5 to 35 micrometers; the mean advanced distance is 18.34 mm. They were all revaluated by PSG and cephalometric analysis postoperatively. RESULTS: All patients have good respond to the treatment. They have a better appearance and the narrow upper airway was enlarged remarkably, their AHI drop from 66.31 +/- 14.74 pre-operately to 3.16 +/- 1.70 pro-operately, and minimal posterior airway space(PAS) from (5.48 +/- 2.76) mm to (9.97 +/- 2.05) mm. There is remarkable difference (P < 0.001). CONCLUSION: DO is a good method for the patients of OSAHS with micrognathia.

Adolescent↗
PubMed2003

[Arrhythmia in the long-term follow-up after intracardiac repair of tetralogy of Fallot].

OBJECTIVE: The long-term success of intracardiac repair of tetralogy of Fallot is hampered by the occurrence of arrhythmias. The aim of the present study was to determine the incidence of arrhythmias after intracardiac repair of tetralogy of Fallot and their correlation with surgical and clinical findings. METHODS: The study group consisted of 54 patients, 35 males and 19 females. They underwent repair at a mean age of 51 months (range 17 to 117 months). The median age at the time of study was 9.4 years (range 5 to 14 years), and the mean duration of follow-up was 4.3 years (range 2.8 to 9.0 years) after surgery. The follow-up study included routine ECG, 24 hour Holter, echocardiography and exercise testing. RESULTS: The incidence of ventricular arrhythmia was 33 percent, and 1 patient had non-sustained ventricular tachycardia. All patients with elevated right ventricular pressure had ventricular arrhythmias, and 28% of patients with normal right ventricular pressure had ventricular arrhythmias (P < 0.05). 53% of patients had significant ventricular arrhythmias when the duration of cardiopulmonary bypass was > or = 90 minutes, as opposed to 23% when it was < 90 minutes (P < 0.05). There was no significant difference in prevalence of ventricular arrhythmias between mild pulmonary regurgitation and severe pulmonary regurgitation (21% vs 40%, P > 0.05). No significant difference was found in the incidence of ventricular arrhythmias between follow-up in five years and more than five years (32% vs 34%, P > 0.05). Age at surgery correlated with the prevalence of ventricular arrhythmias (r = -0.221, P < 0.05). Eight patients (15%) had supraventricular arrhythmias. CONCLUSION: The frequency of ventricular arrhythmias correlated with elevated right ventricular systolic pressure, the duration of cardiopulmonary bypass, and the age at surgery. No correlation was found between pulmonary regurgitation and the duration of follow-up. Exercise-induced frequent multiform premature ventricular complexes were associated with abnormal hemodynamic status and high risk of ventricular tachycardia.

Arrhythmias, Cardiac↗
PubMed2003

[Evaluation of physiological index on treadmill exercise testing of 294 healthy children in Shanghai area].

OBJECTIVE: Dynamic exercise is often used to evaluate the backlog function of cardiovascular system, and the treadmill test is a commonly used dynamic exercise protocol. The study aimed to assess the exercise capacity and cardiovascular response to treadmill exercise in healthy children, and create normal reference values of exercise testing in native children. METHODS: Two huadveds and ninety-four healthy children aged 5 to 14 years were tested using the Bruce protocol on treadmill. RESULTS: Mean exercise capacity in boys increased from 12.2 METs at the age of 5 to 6 years, to 15.2 METs at the age of 13 to 14 years. Mean exercise capacity in girls increased from 11.7 METs at the age of 5 to 6 years, to 12.6 METs at the age of 13 to 14 years. Sex difference was obvious in exercise capacity of children except those at the age of 5 to 6 years. There was no obvious correlation between exercise capacity and the ratio of weight to height. Maximal heart rate ranged from 187 to 235 beats/min. Systolic blood pressure increased gradually until peak exercise was achieved. The mean systolic blood pressure of boys at maximal exercise increased by 38.6 percent compared to resting level, and the girls increased by 34.4 percent. After maximal exercise, mean systolic blood pressure reached resting level in 6 minutes but diastolic blood pressure varied. All children had sinus rhythm at rest. No arrhythmia was recorded during treadmill exercise. However, arrhythmia was found in five children in early recovery period. The incidence of exercise-induced arrhythmia was 1.7 percent. CONCLUSION: Sex difference and age difference was obvious in exercise capacity. In the 21st century, the exercise capacity of children in Shanghai area has approached to the developed country. Using MET as the standardized criterion of exercise capacity is advantageous to standardize maximal or submaximal exercise workloads of all kinds of protocols. Exercise-induced arrhythmia in the early recovery period in children without structural heart disease may not be pathological, but it is necessary for those children to be followed-up.

Adolescent↗
PubMed2003

[Ginkgo flavones in in vitro metabolism and its clinical application].

AIM: To develop a method for assaying Ginkgo flavones in rat hepatical microsome. METHODS: Quercetin, isorhamnetin and keampferol were added to microsome incubate and incubated for a given time then extracted with ether-acetone. After evaporated, the residue was reconstituted with 100 microL of phosphate buffer solution (pH 2.0)-tetrahydrofuran-methanol-isopropanol (60:15:10:20). An aliquot of 20 microL was injected into the HPLC system. According to the result of estimate by means of HPLC, the results of metabolism of Ginkgo flavones in different conditions was compared. RESULTS: The assay was linear over the rang of 0.2-8 mg.L-1 for Ginkgo flavones. The limit of quantification was 0.1 mg.L-1 (n = 3). The recoveries of three components of Ginkgo flavones were 99.9%-113.8% for quercetin (RSD < 0.8%), 100.8%-117.3% for isorhamnetin (RSD < 1.9%) and 100.7%-116.5% for keampferol (RSD < 1.03%, n = 5). CONCLUSION: The method is simple, fast and accurate. It can be used for investigation of the metabolism of Ginkgo flavones.

Animals↗
PubMed2003

[A rapid procedure to purify serum IgG from Microtus fotis].

OBJECTIVE: To evaluate the procedure to purify IgG antibodies from Microtus fotis serum. METHODS: IgG antibodies from sera of three groups of Microtus fotis were purified by protein G or protein A affinity chromatography, their purity and binding capacity were compared. RESULTS: The protein G affinity chromatography was more efficient than protein A affinity chromatography. The antibodies isolated from protein G affinity chromatography showed a higher purity and better activity than that from protein A affinity chromatography monitored by SDS-PAGE and ELISA. The ability of the purified IgG to bind the second antibodies were 8.5 times and 3.1 times that of non-IgG proteins and unpurified sera, respectively. CONCLUSION: The protein G affinity chromatography is a rapid, convenient and reliable procedure for Microtus fotis serum IgG purification.

Animals↗
PubMed2002

Surface-catalyzed amyloid fibril formation.

Light chain (or AL) amyloidosis is characterized by the pathological deposition of insoluble fibrils of immunoglobulin light chain fragments in various tissues, walls of blood vessels, and basement membranes. In the present investigation, the in vitro assembly of a recombinant amyloidogenic light chain variable domain, SMA, on various surfaces was monitored using atomic force microscopy. SMA formed fibrils on native mica at pH 5.0, conditions under which predominantly amorphous aggregates form in solution. Fibril formation was accelerated significantly on surfaces compared with solution; for example, fibrils grew on surfaces at significantly faster rates and at much lower concentrations than in solution. No fibrils were observed on hydrophobic or positively charged surfaces or at pH >7.0. Two novel types of fibril growth were observed on the surface: bidirectional linear assembly of oligomeric units, and linear growth from preformed amorphous cores. In addition to catalyzing the rate of fibrillation, the mechanism of fibril formation on the surfaces was significantly different from in solution, but it may be more physiologically relevant because in vivo the deposits are associated with surfaces.

Amyloid beta-Peptides↗
PubMed2002

A primitive fish close to the common ancestor of tetrapods and lungfish.

The relationship of the three living groups of sarcopterygians or lobe-finned fish (tetrapods, lungfish and coelacanths) has been a matter of debate. Although opinions still differ, most recent phylogenies suggest that tetrapods are more closely related to lungfish than to coelacanths. However, no previously known fossil taxon exhibits a concrete character combination approximating the condition expected in the last common ancestor of tetrapods and lungfish -- and it is still poorly understood how early sarcopterygians diverged into the tetrapod lineage (Tetrapodomorpha) and the lungfish lineage (Dipnomorpha). Here we describe a fossil sarcopterygian fish, Styloichthys changae gen. et sp. nov., that possesses an eyestalk and which exhibits the character combination expected in a stem group close to the last common ancestor of tetrapods and lungfish. Styloichthys from the Lower Devonian of China bridges the morphological gap between stem-group sarcopterygians (Psarolepis and Achoania) and basal tetrapodomorphs/basal dipnomorphs. It provides information that will help in the study of the relationship of early sarcopterygians, and which will also help to resolve the tetrapod-lungfish divergence into a documented sequence of character acquisition.

Animals↗
PubMed2002

Neuroendocrine differentiation factor, IA-1, is a transcriptional repressor and contains a specific DNA-binding domain: identification of consensus IA-1 binding sequence.

A novel cDNA, insulinoma-associated antigen-1 (IA-1), containing five zinc-finger DNA-binding motifs, was isolated from a human insulinoma subtraction library. IA-1 expression is restricted to fetal but not adult pancreatic and brain tissues as well as tumors of neuroendocrine origin. Using various GAL4 DNA binding domain (DBD)/IA-1 fusion protein constructs, we demonstrated that IA-1 functions as a transcriptional repressor and that the region between amino acids 168 and 263 contains the majority of the repressor activity. Using a selected and amplified random oligonucleotide binding assay and bacterially expressed GST-IA-1DBD fusion protein (257-510 a.a.), we identified the consensus IA-1 binding sequence, TG/TC/TC/TT/AGGGGG/TCG/A. Further experiments showed that zinc-fingers 2 and 3 of IA-1 are sufficient to demonstrate transcriptional activity using an IA-1 consensus site containing a reporter construct. A database search with the consensus IA-1 binding sequence revealed target sites in a number of pancreas- and brain-specific genes consistent with its restricted expression pattern. The most significant matches were for the 5'-flanking regions of IA-1 and NeuroD/beta2 genes. Co-transfection of cells with either the full-length IA-1 or hEgr-1AD/IA-1DBD construct and IA-1 or NeuroD/beta2 promoter/CAT construct modulated CAT activity. These findings suggest that the IA-1 protein may be auto-regulated and play a role in pancreas and neuronal development, specifically in the regulation of the NeuroD/beta2 gene.

Base Sequence↗
PubMed2002

Protective effect of a plant formula on ethanol-induced gastric lesions in rats.

A plant formula and its five components were evaluated independently for their gastric protective effect against ethanol-induced stomach lesions in rats. Aqueous extracts of the plant formula (0.25-2g crude drug/kg orally) and its individual components (at the same dose) all showed significant stomach protective effects dose dependently. However, when these extracts were given to rats at a dose of 0.25 g/kg, the five single-herb preparations did not show any activity, but the formula-extract still exhibited a strong protective effect. These findings suggest the presence of a synergistic effect among the plant components. Chemical examination of the extracts indicated that the major ingredients of the five plants were essential oils, terpenoids, flavonoids, glycosides and saccharides and these may contribute to the stomach protective activity observed.

Alpinia↗