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Biomedical subjects

S Lu

Publications and source records attributed to S Lu.

At least 163 records · Page 9Linked to original sources
PubMed1999

[Experimental study on apoptosis induced by ursolic acid isolated from asparagus in HL-60 cells].

OBJECTIVE: To study the inhibitory effect of ursolic acid isolated from Asparagus on the proliferation of HL-60 cells. METHODS: Effects of ursolic acid on the growth and apoptosis were evaluated by MTT assay, DNA gel electrophoresis and morphology observation respectively. RESULTS: The IC50 value of ursolic acid for HL-60 cells was found to be 8.26 mumol/L and 10-50 mumol/L of ursolic acid could induce apoptosis of HL-60 cells expressed to ursolic acid for 1 day. CONCLUSION: Ursolic acid can markedly inhibit HL-60 cells as well as induction of cells apoptosis.

Antineoplastic Agents, Phytogenic↗
PubMed1999

[A study on the symptoms and diagnostic criteria of irritable bowel syndrome in Chinese].

OBJECTIVE: To explore the related symptoms of irritable bowel syndrome (IBS) and its diagnostic criteria in Chinese. METHODS: Symptomatic IBS was diagnosed using Manning criteria in a screening of 2486 subjects in Beijing. A questionnaire study was carried out randomly by clustering samples of residential groups according to a stratified design of city, suburban and rural areas. The sample size of each area studied was in proportion with the population of the area. Symptoms were recorded in detail by trained doctors and medical students and the results underwent computer analysis by comparing their percentages in an IBS (n = 215) group with those in a non-IBS (n = 2271) group. Single factor analysis was done by using Chi square test, those factors of significance were further analyzed by logistic analysis of multifactor. RESULTS: In the single factor analysis, as much as 22 symptoms regarding the whole GI tract and urinary bladder were considered to be significantly related to IBS. After multifactor- analysis, those symptoms of colonic origin remain to be most significant; they were: (1) abdominal pain (> 6 times/a), (2) abdominal pain accompanied by altered bowel habits (both diarrhea and constipation), (3) pain released after defecation, (4) mucus in stool. CONCLUSION: (1) Abdominal pain accompanied by altered bowel habit and pain relieved after defecation are the essential symptoms of IBS. Manning criteria modified by adding constipation with a positive predictive value of 80%, is most suitable in the epidemiologic study as well as in clinical screening of IBS in Chinese; Rome criteria with a positive predictive value of 75% is more reliable in research work and clinical trial. (2) Exclusion of organic disease is important in the diagnosis. (3) There is an overlapping of symptoms between IBS and functional dyspepsia, but those whose colonic symptoms predominate should be diagnosed as IBS, and vise versa. (4) IBS may present extraintestinal symptoms, such as symptoms of the urinary bladder, etc.

Abdominal Pain↗
PubMed1999

[Biological mechanism of macrophage activation by wear particles at the bone-implant interface].

OBJECTIVE: To observe the response of membrane Ca(2+) channel of macrophage-like cells (MCs) to wear particles and analyze the cytoplasmic [Ca(2+)]i change in macrophage activation at the bone-implant interface. METHODS: The synoviocyte system of normal hip joint was established in vitro. Immunohistochemical technique (SABC) with CD68 Mab was used to differentiate MCs and fibroblast-like cells (FCs) in the system, and the time when MCs begin to perform phagocytosis was determined by SEM. 1.5 mg/ml (W/V) Ti alloy, Co-Cr alloy or UHMWPE particles suspension was added into the system to monitor the [Ca(2+)]i change in the MCs by confocal laser scanning microscope (CLSM). RESULTS: Phagocytosis of MCs happened after 6 hours, but within 1 hour the Ca(2+) channel of their cell membrane opened for 1 - 6 times and caused rapid and transient pulses of [Ca(2+)]i in cytoplasm after different period of incubation. There was no significant difference between times or range of the [Ca(2+)]i pulse (P > 0.05). The group of UHMWPE particles had the longest incubation period (P < 0.05), but the interval of pulses was shorter than that in the group of Co-Cr alloy particles (P < 0.05). [Ca(2+)]i pulses still appeared when MCs were incubated by indomethecin (P > 0.05), but the phenomenon could be blocked by nimodipin. CONCLUSIONS: Activation of macrophages at the bone-implant-interface could happen before they phagocytose wear particles. The primary switch-on mechanism of osteolysis mediated by cytokines at the bone-implant interface may be the opening of membrane Ca(2+) channel and pulse-like Ca(2+) influx of macrophages when stimulated by wear particles.

Biocompatible Materials↗
PubMed1999

[Experimental observation of origins of osteoblasts in guided bone regeneration in long bone].

OBJECTIVE: To study the origins of osteoblasts in guided bone regeneration (GBR) so as to understand the mechanism of GBR. METHODS: New Zealand rabbits were used. Standard ununited defect models were made in bilateral middle radial shaft of each rabbit. Randomly, one defect enveloped with silicon membrane as test, another without membrane as control. 12 rabbits were selected for X-ray examination weekly after procedure. 30 rabbits were divided into 6 groups, and sacrificed at 3 days, 1, 2, 3, 4, 5 weeks after surgery for histological observation by immunohistochemical staining of BMP, BGP. RESULTS: The sealed spaces were made by silicon membranes in the defects to prevent peripheral tissue ingrowing early. The defect spaces were filled by granulation tissue formed from proliferative endoperiosteal and medullary stromal cells in bone end. Histological characteristics after callus forming showed that there were 2 - 3 layers of osteoblasts in the surface of callus, and granulation tissue in the center of bone defect. The transforming region existed between the extending callus and granulation tissue, which consisted of a few of cells and a lot of stroma. Early proliferative endo-periosteal and medullary stromal cells in the bone end were positive against BMP, BGP. Some cells in the transforming region were positive against BMP, BGP after callus forming. CONCLUSIONS: Osteoblasts derive from endoperiosteum and medullary stroma in the early stage of GBR and from granulation tissue formed by proliferative endo-periosteal and medullary stromal cells in the later stage.

Animals↗
PubMed1999

[Effect of dietary arginine supplementation on wound healing and the relationship between dose and response in burn rats].

OBJECTIVE: To examine the dose-effect of dietary L-arginine supplementation on burn wound healing. METHODS: The effect of dietary L-arginine supplementation was studied in rats with deep thickness burn (10% TBSA). The time for epithelization of burn wound was determined. Photography of burn wound was taken for measuring percentage of burn wound healing area. Biopsies of burn wound were taken for measuring the content of hydroxyproline, the ratio between type I and type III collagen, and dermal cell cycle. RESULTS: Supplemental dietary L-arginine after burn in rats shortened the time for epithelization of burn wound, increased the content of hydroxyproline, decreased the ratio between type I and type III collagen, elevated the DNA content of dermis. Supplemental dietary L-arginine in the dose of 200 mg x kg(-1) x d(-1) was more effective than any other, 50 mg x kg(-1) x d(-1) and 800 mg kg(-1) x d(-1) showed no beneficial effect on the healing of burn wound. CONCLUSIONS: Suitable L-arginine supplementation can enhance burn wound healing in rats.

Animals↗
PubMed1999

[Expression of BMP-2, TGF-beta, bFGF in guided bone regeneration].

OBJECTIVE: To study the mechanism of guided bone regeneration combined with osteoinduction by observation of expression of BMP-2, TGF-beta, bFGF. METHODS: 42 adult, male, New Zealand rabbits were randomly divided into 6 groups, each group being 7 rabbits. 10mm standard bone defect model was produced bilaterally in the middle radial shaft of each rabbit. Randomly, one defect enveloped with silicon membrane was tested, and the other served as control, sacrificed at 3 days, 1, 2, 3, 4, 5 weeks after surgery for histological observation, immunohistochemical staining of BMP-2, TGF-beta, bFGF and in situ hybridization of their cDNA probes. RESULTS: Histologically bone defects was sealed by silicon membrane, in which inflammation tissue and callus were formed from cells in bone ends. Similar expression of BMP-2, TGF-beta, bFGF between the test groups and control groups was noted. Inflammatory cells in the hematoma expressed bFGF and proliferating periosteal cells, endosteal cells, medullary mesenchymal cells expressed TGF-beta at 3 days postoperatively. Osteocytes in the bone ends and osteoblasts lining callus surface started to express BMP-2, TGF-beta at first week after surgery. Following the formation of inflammation tissue, in which giant cells, macrophages, mesenchymal cells expressed TGF-beta, bFGF respectively. Although the expression of three osteoinductors was the same between the test and control sides, their content was very different in both sides. The whole content in all test sides was much more than all control sides (P < 0.01), the content of test side was also much more than control side in each group. CONCLUSIONS: It is a key reason for successful guided bone regeneration that membrane tube formed a relatively independent bone regenerative situation to prevent around tissue from interruption, and to prevent osteoinductors from diffusion, so that enhanced osteoinductors induced bone regeneration to repair bone defects.

Animals↗
PubMed1999

[Effect of wear particles on cell-to-cell communication of synoviocyte system in vitro and its significance in aseptic loosening of prosthesis].

OBJECTIVE: To study the biological reason of abnormal fiber proliferation at bone-implant interface of aseptically loosened prosthesis by observing cell-to-cell communication of synoviocyte system in vitro under the stimulation of wear particles. METHODS: The synoviocyte system of normal human hip joint was established in vitro and the change of cell-to-cell communication was monitored by fluorescence redistribution after photobleaching technique (FRAP) and confocal laser scanning microscope (CLSM) after Ti alloy, CoCr alloy or UHMWPE particles suspension (1.5 mg/ml, W/V) was added into the system. RESULTS: Cell-to-cell communication of synoviocyte system significantly decreased under the stimulation of three kinds of particles (P < 0.01). he decreased degree was maximal in UHMWPE group and minimal in Ti alloy group (P < 0.01). The cell-to-cell communication level of fibroblast-like-cells (FCs) was significantly lower than that of macrophage-like-cells (MCs) (P < 0.05). CONCLUSIONS: Besides the effect of cytokines promoting fiber proliferation, the great amount of fibrous granuloma at bone-implant interface which has relations with aseptic loosening may be caused by the decrease of cell-to-cell communication of fibroblast under direct stimulation of wear particles.

Alloys↗
PubMed1999

[Selective arterial embolization for the treatment of thoracolumbar spinal tumor].

OBJECTIVE: To decrease intraoperative blood loss during tumor resection. METHODS: Fifteen patients with primary thoraco-lumbar spinal tumor [giant cell tumor (5 patients), malignant nerinoma (2), chordoma (1), fibrous xanthosarcoma (1), malignant fibrohistocytoma (1), osteosarcoma (1), Ewing sarcoma (1), myeloma (1), leimyosarcoma (1), Non-Hodgkin diseases (1)] were treated by means of preoperative selective arterial embolization, tumor resection, and spinal reconstruction. Eight patients were subjected to total spondylectomy in one stage. RESULTS: Fourteen patients showed satisfactory results after embolization. The volume of intraoperative blood loss ranged from 3,000 ml to 400 ml (average 1,200 ml). Follow up of the patients varied from 8 months to 19 years (average 48.7 months). Local recurrence happened in 3 patients; 3 patients died from metastasis. Three of 4 patients recovered from complete bowel movement and urination. Seven of nine patients had musical strength improved. Six of 8 patients had recovery of the e sensation of the lower limbs. CONCLUSIONS: Selective arterial embolization before operation followed by operation within 24 hours can reduce intraoperative blood loss, shorten operative time, and provide a clear operative field for tumor resection.

Adolescent↗
PubMed1999

[An eight-factor analysis of early skeletal Class II malocclusion using Fränkel appliance].

OBJECTIVE: To investigate the change of eight-factor after Fränkel appliance treatment in skeletal class II malocclusions. METHODS: X-ray cephalometric film. RESULTS: Fränkel appliance can be used to enhance the growth of ramus (Factor 2) and body (Factor 1) of the mandible, decrease the angle of cranial base (Factor 8) and made the maxilla rotate (Factor 4) anteriorly, which were benefit to the treatment of class II malocclusion. However, neither the vertical (Factor 5) and sagittal (Factor 3) growth of maxilla nor the height of posterior alveolar bone (Factor 6) can be inhibited by use of Fränkel appliance. CONCLUSION: Fränkel appliance is suitable to the treatment of class II patients with deficient mandible and almost normal maxilla, while Fränkel appliance would rather not be used for patients with overgrown maxilla or vertical growth pattern.

Adolescent↗
PubMed1999

[Investigating the phenomenon of total erythrocyte destruction during an in-vitro hemolysis test by roller pump].

This study sought to address the question, "will the phenomenon of 'total erythrocyte destruction' come about during a long time of in vitro hemolysis test by roller pump". One-day-old boving blood was employed in the test by Polystan pump(group A) and Cobe pump (group B). TMB method was used to measure the level of plasma-free hemoglobin. The samples of plasma-free hemoglobin were taken at the time before pumping and pumping for 4,6,8,10, 12,14 and 16 hours. The index of hemolysis was calculated according to Koller's formula. The results showed that the levels of plasma-free hemoglobin in the two groups both increased linearly during the puming of blood. The index of hemolysis was 0.2960 mg/L group A, and 0.3993 mg/L in group B; no statistically significant difference was noted between the two groups. These data indicated that no phenomenon of "total erythrocyte destruction" was observed in this hemolysis test by roller pump.

Erythrocytes↗
PubMed1999

[The protective effect against Toxoplasma infection in mice immunized with laser-irradiated Toxoplasma tachyzoites].

AIM: To observe the level of immune responses and protective immunity in mice induced by laser-irradiated Toxoplasma tachyzoites (LIT). METHODS: ICR mice were immunized with LIT. After one month, the mice were challenged with live Toxoplasma tachyzoites to observe the effect of LIT. Indirect immunofluorescence assay and ELISA were used to detect CD4+/CD8+ lymphocyte subpopulation and IgG antibody. RESULTS: Immunization with LIT could partially protect the mice from Toxoplasma infection, prolong the survival time, enhance the CD4+/CD8+ ratio and produce specific IgG antibody. CONCLUSION: Intraperitoneal injection with LIT can induce partial protective immunity and specifically elicit ICR mice to generate humoral and cell-mediated immune responses.

Animals↗
PubMed1999

[Acquirement and identification of a novel intron 1 of human Na(+)-K(+)-exchanging ATPase alpha 1 subunit gene].

OBJECTIVE: The unknown part genome structure of the alpha 1 subunit of human Na(+)-K(+)-Exchanging ATPase gene which covers the 80-130 aa in its extracellular domain was studied. METHODS: By means of PCR, the targeted sequences was amplified by using two different templates: human Genome DNA and the muscle cDNA library; the PCR products were analyzed by restriction endonuclease digestion, then cloned into plasmid vector to perform the chemiluminescence Sequencing. The homologous search, splicing site detection and the analysis of the sequence were applied. RESULTS: Two different lengths of products, 833 bp(Fg) and 195 bp(Fc) were acquired after PCR amplification with the human genome DNA and muscle cDNA library respectively. There was an insertion of a 638 bp fragment in Fg at its 138-775 bp. And there was not obviously known sequence homologous to the insertion sequence. CONCLUSIONS: A novel sequence containing the complete human Na(+)-K(+)-Exchanging ATPase alpha 1 subunit gene intron 1 was found, the exact splicing donor and receptor site within it were identified. The Accession No of this sequence is L76938. Analysis of this sequence showed that the intron 1 may function in the regulation of the gene expression and also had a potential coding sequence.

Base Sequence↗
PubMed1999

[Detection of human papillomavirus in laryngeal carcinoma with digoxigenin labelled probe prepared by polymerase chain reaction].

OBJECTIVE: To study the relationship between laryngeal carcinoma and human papillomavirus (HPV), and describe distribution, expression of genome types of HPV in laryngeal carcinoma. METHODS: We used a non-radioactive digoxigenin labeled probe prepared by polymerase chain reaction (PCR) to test the fresh tissue samples from 146 cases with different laryngeal lesions. The labelled probe of HPV consensus primers was obtained, which enabled detection of nine types of HPV DNAs that were HPV 6, 11, 16, 18, 31, 33, 35, 42 and 58. The genome types of HPV DNA positive cases were determined by using multiple primers PCR. RESULTS: The results turned out to be as follows: The HPV infection positive rate was 45.6%(31/68) for laryngeal carcinoma, 20.0% (3/15) for neck metastatic lymphnode, 11.8%(2/17) for precarcinomatous lesions and 6.3%(1/16) for vocal cord polypus. 15 cases of normal tissues adjacent to carcinoma and another 15 normal tissues opposite to the carcinoma were all HPV DNA negative. HPV16, 18 types are the main types of laryngeal carcinoma and HPV6, 11 types often appear in benign lesions of larynx. CONCLUSION: These results implicated that the occurrence and development of laryngeal carcinoma may be closely related to HPV infection.

DNA Probes, HPV↗
PubMed1998

Sociodemographic and behavioral characteristics of African-American women with HIV and AIDS in Los Angeles County, 1990-1997.

African-American women have the highest AIDS rate of any racial/ethnic group of women in both Los Angeles County (LAC), California and in the United States. Limited population-based epidemiologic studies of African-American women with HIV and AIDS describe this group and examine the factors associated with the excessive rates. Interview data collected from 1990 to 1997 on a population-based sample of AIDS cases and a group of HIV-infected women in LAC were analyzed to highlight the sociodemographic and behavioral characteristics of African-American women. This group of African-American women with HIV or AIDS in LAC were unemployed (88%), single mothers (64%), living on public assistance (86%) with annual household incomes <$10,000 U.S. (76%). A history of crack use predominated (50%). Compared with women of other races with HIV and AIDS, African-American women reported more sexual partners; reported more infections with sexually transmitted diseases; sought treatment for their HIV infection later; were more likely to trade sex; and were almost five times more likely to have ever used crack cocaine. HIV prevention for African-American women in LAC should focus on improving self-esteem and negotiation skills within the context of the crack cocaine culture and the disadvantaged social and economic situation described.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Proto-oncogene PML controls genes devoted to MHC class I antigen presentation.

Fragments of foreign antigens associated with class I molecules of the major histocompatibility complex (MHC) are presented at the cell surface to elicit an immune response. This presentation requires the coordinated expression of several genes contained in the MHC, including those encoding the MHC class I heavy chain, the proteins LMP-2 and LMP-7, which are involved in the proteasomal degradation of cytosolic antigens into peptide fragments that are destined for association with MHC class I molecules, and TAP-1 and TAP-2, which transport these fragments across the membrane of the endoplasmic reticulum at the start of their journey to the cell surface. In many virus-transformed cell lines and spontaneous tumours, these genes are simultaneously repressed. However, the key factor(s) that are essential for their expression and repression have not been identified. Here we report that the proto-oncogene product PML induces expression of LMP-2, LMP-7, TAP-1 and TAP-2 in an MHC-class I-negative, recurrent tumour, leading to the re-expression of cell-surface MHC in tumours and to rejection of the tumours. PML also regulates MHC expression in untransformed fibroblasts. We conclude that malfunction of PML may enable a tumour to evade the immune defence of its host.

3T3 Cells↗
PubMed1998

NF1 inactivation cooperates with N-ras in in vivo lymphogenesis activating Erk by a mechanism independent of its Ras-GTPase accelerating activity.

We crossed transgenic mice overexpressing the N-ras proto-oncogene (RasTg) with mice carrying one inactivated copy of the NF1 tumor suppressor gene (NF1+/-) to assess their possible cooperation in tumorigenesis. We have found a significant increase in the incidence of lymphomas in animals with both lesions (RasTg NF1+/-), as compared with animals with single lesions. The mechanism of this cooperation appears to be independent of the NF1 GTPase activating activity since the level of Ras-GTP in primary cultures of tumor tissue do not differ among animals with double and with single lesions. Nevertheless, the finding of significantly higher levels of Erk-1 and Erk-2 activation in lymphomas in the RasTg NF1+/- than in the RasTg group suggests that this cooperative effect may be in part explained by increased signaling through the Erk pathways. Consistent with a role for Erk activation in transformation is the additional observation that Erk-1 and Erk-2 activation is significantly increased in lymphomas as compared with normal spleen. This activation is likely to occur by phosphorylation of previously synthesized and inactive Erk proteins since, despite differences in activation, Erk-1 and Erk-2 expression is similar in normal and lymphoid tissue in all groups. The observed cooperation in in vivo lymphomagenesis between N-ras overexpression and NF1 inactivation emphasizes the importance of searching for additional functions for the NF1 protein and of intensifying the screening for NF1 mutations in human lymphomas.

3T3 Cells↗
PubMed1998

Digital video: a tool for correlating neuronal firing patterns with hand motor behavior.

This report describes the use of multimedia technology for simultaneous recording of single unit responses in cerebral cortex, and imaging of hand kinematics as monkeys grasp and manipulate objects. These imaging methods allow direct correlation of full-frame, full-field video images with the actual spike trains recorded with microelectrodes. Our implementation of digital video provides high-resolution snapshots of the hand motor behavior every 33.3 ms, and a precise calibration and display of the synchronously recorded electrophysiological activity digitized at rates up to 44.5 kHz on the same platform. These imaging methods permit non-invasive, non-traumatic monitoring of both trained and spontaneous activity in experimental animals, while providing synchronized digitized records of neuronal spike trains. We also describe software instruments that quantify and analyze the digitized spike trains. One instrument employs user-selectable objective criteria for distinguishing spikes from noise, separates individual action potential waveforms by their amplitude and duration, and compiles time stamps for each spike train. A second instrument constructs rasters and histograms of repeated behavioral trials using the timing of the corresponding video frame for alignment. These analyses reveal functional classes of cortical neurons signaling specific stages of prehension.

Animals↗