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Biomedical subjects

Lei Yu

Publications and source records attributed to Lei Yu.

At least 55 records · Page 3Linked to original sources
PubMed2005

[FK506 promotes apoptosis of macrophages activated by homogenate of allogenic nerve].

OBJECTIVE: To study the effect of FK506 in promoting apoptosis of peripheral blood-derived macrophages activated by homogenate of allogenic nerve tissues. METHODS: Homogenate of the allogenic nerve tissues was prepared using the sciatic nerve and injected in one-month-old SD rats, from which the macrophages activated by the homogenate were collected from the abdominal cavity and cultured in vitro. The cells were divided into 4 groups according to different concentrations of FK506 for treatment, namely 0 (group A, control group), 0.25 ng/ml (group B), 0.5 ng/ml (group C), and 1.0 ng/ml (group D). The cells of the 4 groups were inoculated into 96-well plate respectively for detecting the viability of the macrophages by MTT assay and for morphological evaluation of the cell apoptosis by transmission electron microscopy and fluorescence microscopy. RESULTS: The cells in groups B and C exhibited reduced viability and signs of apoptosis, and necrosis was observed in group D. Transmission electron microscopy and fluorescence microscopy identified early apoptotic changes and the presence of apoptotic body in the macrophages. The apoptotic rates of groups B and C were much higher than that in group A found by flow cytometry. CONCLUSION: FK506 can promote the apoptosis of macrophage activated by allogenic nerve homogenate and reduce macrophage-mediated immunological rejection of peripheral nerve allograft.

Animals↗
PubMed2005

[Construction of artificial nerve bridge by three-dimensional culture of Schwann cells with human hair keratins].

OBJECTIVE: To culture Schwann cells (SCs) and human hair keratins (HHKs) for artificial nerve bridge construction. METHODS: SCs were purified by primary culture and labeled with BrdU, which were then cultured with HHKs decorated by ECM. The artificial nerve bridge was implanted into the defect of sciatic nerve, beneath the skin, and in the skeletal muscles of SD rat, respectively. The morphology of the SCs cultured with HHKs was monitored by inverted microscope and evaluated by immunocytochemical staining. Growth of BrdU-labeled SCs in vivo was observed by immunocytochemical staining on paraffin sections. RESULTS: In vitro cultured SCs were capable of adhering to HHKs and grew well four weeks after implantation. The HHK component in the artificial nerve bridge underwent degradation in the defect of the sciatic nerve, beneath the skin, and in the skeletal muscles of SD rat, and SC survival and proliferation were verified. CONCLUSION: SCs can survive in three-dimensional culture with HHKs for construction of artificial nerve bridge to repair nerve defects.

Animals↗
PubMed2005

[Biodegradation of butylbenzyl phthalate by acclimated activated sludge].

The results of degradation of butyl benzyl phthalate(BBP) by activated sludge demonstrate that the activated sludge is a high efficiency flora for degrading BBP, which can degrade BBP quickly and more than 95 % BBP is degraded in one day. The degradation of BBP can be described by the first-order dynamics model, the concentration in range of 100,300,500 mg x L(-1), the dynamics equation of degradation respectively is Inc = - 0.0699x + 5.6171, nc = 0.0683x + 8.4083, and Inc = - 0.0583x + 7.2806, t1/2 is 9.92, 10.15, 11.89 h, the constant of degrading rate kb is 0.0699, 0.0683 and 0.0583 d(-1). The constant of degrading rate decreases as the concentration of BBP increases, which shows that BBP of high concentration inhibits its biodegradation. In addition, two degraded productions, monobutyl phthalate and methanoyal phthalate, are identified from the degradation of BBP with HPLC-MSn. The route of degradation is that BBP produces mono-ester firstly, and then the product turns into phthalic acid, finally it oxidizes into CO2 and H2O.

Biodegradation, Environmental↗
PubMed2005

[Oxidative stress-induced differentiation of L6 myoblasts].

OBJECTIVE: To explore the relationship between the differentiation of L6 myoblasts and oxidative stress. METHODS: MTT assay was used to determine the viability of L6 myoblasts, from which the total RNA was extracted for amplification of the myogenin gene fragment by RT-PCR. H(2)O(2)-induced morphological changes of the cells were observed. RESULTS: The myoblasts treated with low concentration of reactive oxygen (50 micromol/L H(2)O(2)) for 1 h exhibited accelerated cell growth (P<0.05), and treatment with 50 and 150 micromol/L H(2)O(2) induced the gene expression of myogenin, a molecular marker for differentiation of myoblasts. Morphological study revealed myotube formation and accelerated differentiation of the myoblasts induced by H(2)O(2). CONCLUSION: The reactive oxygen may serve as the intracellular signal molecules to induce the growth and differentiation of the myoblasts.

Animals↗
PubMed2005

[Auricular point sticking plus moxibustion for treatment of recurrent herpes simplex].

OBJECTIVE: To search for the best therapy for recurrent herpes simplex. METHODS: Ninety-six cases were randomly divided into an auricular point sticking plus moxibustion group (treatment group, n = 54), a medication group (control group, n = 42). The treatment group were treated with auricular sticking at points Spleen, Lung, Kidney, and others, and moxibustion was applied at Zusanli (ST 36), Fenglong (ST 40), and local blister; the control group were treated by oral administration and external application of aciclovir. RESULTS: The cured rate and the total effective rate were 55.5% and 100.0% in the treatment group, and 9.5% and 61.9% in the control group, respectively, with a significant difference between the two groups (P<0.05). CONCLUSION: The auricular point sticking plus moxibustion is a better therapy for recurrent herpes simplex, with a significantly better therapeutic effect than that of the medication.

Acupuncture Points↗
PubMed2004

Bimodal effects of MK-801 on locomotion and stereotypy in C57BL/6 mice.

RATIONALE: Systemic injection of the non-competitive NMDA (N-methyl-D-aspartate) receptor antagonist MK-801 (dizocilpine maleate) causes both increased locomotion in rodents and various stereotypic behaviors that are proposed to model certain aspects of schizophrenic symptoms in humans. OBJECTIVES: This study presents a comprehensive characterization of the bimodal effects of MK-801 on locomotion and stereotypy in the C57BL/6 mouse strain, a strain commonly used for genetically modified mice. RESULTS: We found that it is important to analyze both locomotion and stereotypy in parallel, as MK-801-induced stereotypy results in abnormal movements that are recorded as locomotion by automated beam detection systems. Furthermore, it is important to analyze the bimodal effects of MK-801 over an extended time span, rather than the commonly used narrower time window, as at higher doses (e.g., above 0.3 mg/kg) the hyperlocomotion phase develops only after the stereotypic phase subsides. We also observed that the apparent dose-response curve is very sensitive to the particular time window chosen for analysis because MK-801 affects both the time course and maximum value of stimulated locomotion. We show that analyzing the absolute peak value of locomotion induced for each animal, rather than group-averaged time courses, provides a measure that is sensitive over a wider range of MK-801 doses. Interestingly, MK-801 even at a very low dose of 0.02 mg/kg suppressed rather than enhanced rearing behavior, differing in this regard from amphetamine. CONCLUSIONS: The non-competitive NMDA receptor antagonist MK-801 induces a complex pattern of behavioral modification in mice with respect to both the time course and the dose-response relationship of behavioral changes. The results of this study provide a foundation and frame of reference for the growing interest in studying MK-801-induced behavior in mice.

Animals↗
PubMed2004

Differential mechanisms of nitric oxide- and peroxynitrite-induced cell death.

Nitric oxide (NO) contributes to cellular degeneration in various disorders, particularly in the nervous system. NO targets cell proteins such as soluble guanylyl cyclase, but its detrimental effects are generally attributed to its reaction product with superoxide, peroxynitrite. To understand the mechanisms of NO-induced cell stress, we studied the effects of the NO donors diethylenetriamine and spermine NONOate and the peroxynitrite donor 5-amino-3-(4-morpholinyl)-1,2,3-oxadiazolium chloride (SIN-1) in SH-SY5Y and NG108-15 neuroblastoma cells. All three compounds induced a dose- and time-dependent decrease in viable cells, which was not blocked by the soluble guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one. The two NONOates were approximately 15-fold more potent in SH-SY5Y than in NG108-15 cells, whereas the EC50 values of SIN-1 in SH-SY5Y and NG108-15 cells were in the same order. This led us to conclude that the mechanisms of NO and peroxynitrite did not converge. This was supported by our other findings. NONOates induced DNA fragmentation and an increase in cellular caspase-3 activity that preceded the gradual decline in cell viability. In contrast, SIN-1 induced a transient decline in ATP levels and a delayed loss of cell viability with no significant increase in caspase-3 activity or DNA laddering. Moreover, post-treatment with insulin inhibited caspase-3 activation and loss of cell viability in NONOate- but not in SIN-1-exposed cells. These findings suggest that NO is a potent toxin independent of peroxynitrite formation.

Animals↗
PubMed2004

[Surgical treatment with sliding esophageal hiatal hernia].

OBJECTIVE: To study the effect and method of surgical treatment in patients with sliding esophageal hiatal hernia. METHODS: To divide into two groups: fifty-two patients with sliding esophageal hiatal hernia diagnosed with gastroscopy and X-ray barium meal examination accepted operation. Forty-seven cases were treated by Nissen's operation. Three cases were treated by Hill's operation. One case was treated by Boerema's operation. One case was treated by Rampal's operation. 24-hour esophageal pH and esophageal motility were also monitored before and after operation. Thirty healthy volunteer were performed control group and were monitored by 24-hour esophageal pH and esophageal motility. RESULTS: The patients in operation group had lower esophageal sphincter relaxation and acid reflux before operation. They became significantly ameliorative after operation. Forty-seven cases (90%) had the satisfactory effect. Two cases (4%) recrudesced. CONCLUSION: Comprehensive examination and perfect surgical choice may play an important role in the treatment of sliding esophageal hiatal hernia; The better method for sliding esophageal hiatal hernia is Nissen's operation.

Adult↗
PubMed2004

Direct AFM observation of saposin C-induced membrane domains in lipid bilayers: from simple to complex lipid mixtures.

Saposin C (Sap C) is a small glycoprotein required by glucosylceramidase (GCase) for hydrolysis of glucosylceramide to ceramide and glucose in lysosomes. The molecular mechanism underlying Sap C stimulation of the enzyme activation is not fully understood. Here, atomic force microscopy (AFM) has been used to study Sap C-membrane interactions under physiological conditions. First, to establish how Sap C-membrane interactions affect membrane structure, lipid bilayers containing zwitterionic and anionic phospholipids were used. It was observed that Sap C induced two types of membrane restructuring effects, i.e., the formation of patch-like domains and membrane destabilization. Bilayers underwent extensive structural reorganization. To validate the biological importance of the membrane restructuring effects, interaction of Sap C with lipid bilayers composed of cholesterol, sphingomyelin, and zwitterionic and anionic phospholipids were studied. Although similar membrane restructuring effects were observed, Sap C-membrane interactions, in this case, were remarkably modulated and their effects were restricted to a limited area. As a result, nanometer-sized domains were formed. The establishment of a model membrane system will allow us to further study the dynamics, structure and mechanism of the Sap C-associated membrane domains and to examine the important role that these domains may play in enzyme activation.

Complex Mixtures↗
PubMed2004

Laparoscopic-assisted total cyst excision of choledochal cyst and Roux-en-Y hepatoenterostomy.

PURPOSE: The aim of this study was to describe the technical experience and outcome in laparoscopic-assisted total cyst excision of choledochal cyst with Roux-en-Y hepatoenterostomy. METHODS: Thirty-five patients with choledochal cyst were studied. Their age ranged from 3 months to 9 years (average age, 3.6 years). The choledochal cysts were cyst type in 33 cases and fusiform type in the other 2 cases. Four trocars were utilized with 3- to 5-mm instrumentation. Under laparoscopic guidance, the gallbladder and the dilated bile duct were excised completely. The Roux-en-Y jejunojejunostomy was performed extracorporeally by exteriorizing the jejunum through the extending umbilical incision (1.5 to 2 cm), and an end-to-side hepaticojejunostomy was carried out intracorporeally by the hand suture methods. RESULTS: Average duration of operation was 4.3 hours (range, 3.5 to 7.6 hours), intraoperative blood loss was 5 to 10 mL, and 8 of the 35 patients had associated hepatic ductal stenosis and underwent laparoscopic excision of the cyst and ductoplasty. In 1 of the 8 cases, bile leak was noticed from day 1 through 26 postoperatively. The postoperative course was uneventful in the other 34 patients with a hospital postoperative stay ranging from 3 to 6 days. There were no postoperative complications in the 3-month to 1(1/2)-year follow-up. CONCLUSIONS: Laparoscopic-assisted total cyst excision with Roux-en-Y hepatoenterostomy is feasible for the treatment of choledochal cyst in children.

Anastomosis, Roux-en-Y↗
PubMed2004

Sexual behavior and sex-associated environmental cues activate the mesolimbic system in male rats.

The mesolimbic system plays an important role in the regulation of both pathological behaviors such as drug addiction and normal motivated behaviors such as sexual behavior. The present study investigated the mechanism by which this system is endogenously activated during sexual behavior. Specifically, the effects of sexual experience and sex-related environmental cues on the activation of several components of the mesolimbic system were studied. The mesolimbic system consists of a dopaminergic projection from the ventral tegmental area (VTA) to the nucleus accumbens (NAc). Previous studies suggest that these neurons are under tonic inhibition by local GABA interneurons, which are in turn modulated by mu opioid receptor (MOR) ligands. To test the hypothesis that opioids are acting in the VTA during sexual behavior, visualization of MOR internalization in VTA was used as a marker for ligand-induced activation of the receptor. Significant increases in MOR internalization were observed following copulation or exposure to sex-related environmental cues. The next goal was to determine if sexual behavior activates dopamine neurons in the VTA, using tyrosine hydroxylase as a marker for dopaminergic neurons and Fos-immunoreactivity as a marker for neuronal activation. Significant increases in the percentage of activated dopaminergic neurons were observed following copulation or exposure to sex-related environmental cues. In addition, mating and sex-related cues activated a large population of nondopaminergic neurons in VTA as well as neurons in both the NAc Core and Shell. Taken together, our results provide functional neuroanatomical evidence that the mesolimbic system is activated by both sexual behavior and exposure to sex-related environmental cues.

Animals↗
PubMed2004

Identification and characterization of a rat novel gene RSEP4 expressed specifically in central nervous system.

The low-abundantly expressed genes composed the majorities of the mRNAs expressed in the central nervous system (CNS), and were thought to be important for the normal brain functions. Through differential screening a low-abundance cDNA sublibrary with mRNA from neuropathic pain of chronic constriction injury (CCI) model, we have identified a novel rat gene, rat spinal-cord expression protein 4 gene (RSEP4). The total length of RSEP4 cDNA is 2006 bp, with a 501 nucleotide open reading frame (ORF) that encodes a 167 amino acid polypeptide. Northern blot revealed that RSEP4 was expressed specifically in the CNS. In situ hybridization showed that the mRNA of RSEP4 was strongly expressed in the CA1, CA2, CA3 and DG regions of hippocampus, the Purkinje cells of cerebellum, and the small sensory neurons of dorsal horn and large motor neurons of ventral horn of spinal cord. Over-expression of RSEP4-EGFP fusion protein in the human embryonic kidney 293T cells showed that RSEP4 protein was mainly localized in the cell cytoplasm. These results suggest that RSEP4 may play some roles in the CNS.

Amino Acid Sequence↗
PubMed2004

SNAP-25 in hippocampal CA1 region is involved in memory consolidation.

As a synaptosomal protein, SNAP-25 plays a role in a number of neuronal functions including axonal growth, dendrite formation, fusion of synaptic vesicles with membrane and the expression of long-term potentiation (LTP) in the hippocampus. Using a learning/memory behavior screening, we identified SNAP-25 as one of the differentially expressed genes in the hippocampus upon behavioral training. The inhibition of SNAP-25 with intracerebroventricular antisense oligonucleotide caused a deficit in long- but not short-term memory for step-down inhibitory avoidance. Intra-CA1 infusion of the SNAP-25 antisense oligonucleotide impaired long-term contextual fear memory and spatial memory and interfered with the LTP of synaptic transmission in the CA1 region. The inhibitory effect on LTP was not mediated by a pre-synaptic mechanism because paired pulse facilitation of synaptic transmission was not affected after administration of the antisense oligonucleotide. Together, the results suggest that SNAP-25 in the CA1 region is involved in memory consolidation.

Animals↗
PubMed2004

[In vitro study of formalin-fixed bone tissues for allogeneic bone grafting].

OBJECTIVE: To conduct an in vitro study to assess the preliminary possibility of using formalin-fixed, instead of fresh, human bone tissues for allografting. METHODS: Fresh cadaveric bone tissues were fixed by formalin for more than 6 months and dissected into 5 mmx5 mmx5 mm pieces and 5 mmx5 mmx40 mm sticks, followed by chemical treatments to prepare the allograft bone materials. When alls treatments were completed, the bone grafts were centrifuged and their properties and cellular compatibility assessed in comparison with the currently used bone grafts clinically. RESULTS: The residual formaldehyde of the fixed allograft bone material was much below the controlled level and no significant differences were noted between the bone graft materials tested in regard to the chemical and mechanical properties and biocompatibility. CONCLUSION: This material we have prepared may meet the clinical demands for bone grafting, with good biocompatibility and less chance for infection by pathological agents.

Animals↗
PubMed2004

[Induced differentiation of adult human bone marrow derived mesenchymal stem cells in vitro toward osteoblasts].

OBJECTIVE: To investigate the feasibility of inducing in vitro mesenchymal stem cells (MSCs) derived from adult human bone marrow differentiate into osteoblasts and potential applicability of the MSCs as the seed cells in tissue engineering. METHODS: Adult human bone marrow was collected from the healthy adult volunteers to obtain the MSCs, which, after in vitro culture in DMEM supplemented with 10% fetal bovine serum and incubation under standard condition, were induced to differentiate into osteoblasts in DMEM containing dexamethasone (1x10(-8) mol/L), beta-sodium glycerophosphate (10 mmol/L) and ascorbic acid (50 mg L). Proliferation and differentiation of the MSCs were observed continually under inverted phase-contrast microscope and transmission electron microscope. The collagen typeI was detected by immunohistochemistry, alkaline phosphatase (AP) in the MSCs stained by Gomori, the calcified nodules were stained by von Kossa method, and the changes in the content of AP were measured. RESULTS: The MSCs proliferated rapidly in in vitro culture and after a 2- to 3-week induction, the cells began to generate large amount of enlarged endoplasmic reticulum, Golgi complexes and mitochondria, with immature cell nuclei. Positive staining for collagen typeIand strong reaction for AP and calcified nodules were observed. Increasing AP secretion by the MSCs was seen as the time of induction prolonged (P<0.01). CONCLUSIONS: Human bone marrow-derived MSCs can be induced to differentiate into osteoblasts through relatively simple procedures, which provide ideal autogenous source of seed cells for bone tissue engineering. The method adopted in this experiment may be used for routine culture of the seed cells for bone tissue engineering.

Adolescent↗
PubMed2004

Reporting the incidence of school violence across grade levels in the U.S. using the Third International Mathematics and Science Study (TIMSS).

School violence has increasingly captured public attention due to deadly school shootings. Controversy on school violence is demonstrated by a mixed picture of school safety and the lack of consensus on the definitions of violence, which makes comparison of findings across studies difficult. This study extended the application of the Rasch model to school violence research using TIMSS data. The results show that school violence occurred at a level much lower than the predictions of the measurement model. Across all grade levels the most frequently reported type of violence is intimidation or verbal abuse of students and the least frequently reported physical injury to teachers or staff.

Adolescent↗
PubMed2004

[Construction and expression of anti-human CD3 single chain Fv antibody/human p53 tetramerization domain fusion gene].

AIM: To construct anti-human CD3 single chain Fv antibody (scFv)/human p53 tetramerization domain fusion gene and express the fusion protein in Hela cells. METHODS: The anti-human CD3 scFv was cloned into the previously constructed plasmid pUC18/IgG3/p53 to construct anti-human CD3 scFv /human p53 tetramerization domain fusion gene. After enzyme digestion analysis and sequencing, the fusion gene was subcloned into the expression plasmid pSecTag2-B. Then the plasmid pSecTag2-B containing the fusion gene was transfected into Hela cells. The expressed products were analyzed by SDS-PAGE and Western blot. The binding of the purified fusion protein to human peripheral blood mononuclear cells (PBMCs) was detected by flow cytometry. RESULTS: DNA sequencing showed the fusion gene was constructed successfully. The expressed product of the fusion gene with a relative molecular mass (M(r)) about 35 000 was confirmed by SDS-PAGE and Western blot. The purified tetrameric anti-human CD3 scFv showed significantly stronger binding to PBMCs than scFv. CONCLUSION: The tetrameric anti-human CD3 scFv which can bind to PBMCs has been successfully expressed and purified for potential use in clinical studies.

CD3 Complex↗