Search PubMed⌕ Search

Biomedical subjects

Y Dong

Publications and source records attributed to Y Dong.

At least 127 records · Page 7Linked to original sources
PubMed2000

Experimental study of phosphopeptide in promoting tooth remineralization.

OBJECTIVE: To explore a new method for effective and safe prevention and treatment of caries. METHODS: Following the theory of tooth remineralization, we searched for the mechanism and clinical application of tooth remineralization with phosphopeptide. RESULTS: Phosphopeptide, with calcium and phosphorus, had a high affinity for hydroxyapatite and could enhance tooth remineralization. CONCLUSION: Phosphopeptide was effective in the prevention and treatment of tooth decay. Clinically, it could be safely applied.

Animals↗
PubMed2000

[Autogenous costochondral graft applied in the reconstruction of the temporomandibular joint].

OBJECTIVE: To study the surgical treatment of ankylosis of the temporomandibular joint. METHODS: Autogenous costochondral grafts were applied in the reconstruction of the temporomandibular joint in 27 cases with condyle ankylosis from 1988-1998. The follow up period was 1-10 years. The pre- and post-operative degree of mouth opening and the TMJ function was examined. RESULTS: Postoperative mouth opening was improved up to 2 cm in the 27 cases. All the results were successful without recrudescence of condyle ankylosis. CONCLUSION: The use of autogenous costochondral grafts in TMJ reconstruction is the best method in the treatment of TMJ ankylosis.

Adolescent↗
PubMed2000

Ultraviolet blood irradiation and oxygenation affects free radicals and antioxidase after rabbit spinal cord injury.

OBJECTIVE: To investigate the effects of ultraviolet blood irradiation and oxygenation (UBIO) on free radicals and antioxidase after spinal cord injury in rabbits. METHODS: Totally, 186 rabbits were used and divided randomly into four experimental groups: control (n = 6), blood transfusion (n = 24), injured (n = 96) and treatment (n = 60) groups. The relative intensity of free radical (FR) signals, malondialdehyde (MDA) content, as well as the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) were compared among the four groups at 6, 24, 48, and 72 hours and 6 days after injury. RESULTS: The relative intensity of FR signals in spinal cord tissue in the injured group increased at 48 hours and showed a striking difference compared with the control group; in the treatment group, it decreased and showed a striking difference compared with the injured group. MDA content in blood in the injured group increased and showed a striking difference at 6, 24 and 48 hours and showed a significant difference at 72 hours and 6 days after injury compared with the control group. In the treatment group, MDA content in blood decreased and showed a significant difference at 48 hours compared with the injured group. MDA content in spinal cord tissue increased in the injured group and showed a striking difference compared with the control group; in the treatment group, it decreased and showed a striking difference compared with the injured group at the corresponding times. The activity of SOD in blood and spinal cord tissue decreased in the injured group and showed a striking difference compared with the control group; in the treatment group, it increased and showed a striking difference compared with the injured group at the corresponding times. The changes in activity of GSH-PX in blood and spinal cord tissue were similar to that in SOD. No significant difference was observed between the blood transfusion and control groups. CONCLUSION: UBIO can ease free radical damages and elevate the activity of antioxidases after spinal cord injury in rabbits.

Animals↗
PubMed2000

[APC gene expression in precancerous lesions of stomach examined by light and electron microscopic in situ hybridization].

OBJECTIVE: To study the significance of abnormal expression of APC gene in gastric cancer and its precancerous lesions. METHODS: The expression of APC gene was examined in 119 cases of precancerous lesions and 40 cases of gastric cancers by light and electron microscopic in situ hybridization technique. RESULTS: 1. The positive rate of APC gene expression in normal gastric mucosa, mild dysplasia, moderately severe dysplasia, severe dysplasia and gastric cancer was 83.3%, 77.8%, 62.5%, 25.9%, and 6.7%-8.0%, respectively. 2. In 4 types of intestinal metaplasia (IM), APC gene expressed much more frequently in colonic type than in small intestinal type (P < 0.05), more frequently in incomplete type of IM than in complete type (P > 0.05). The positive rate of incomplete colonic type was the highest. 3. Under electron microscope, the APC positive signals were located in the cytoplasm matrix of gastric mucosa cells. They decreased gradually from normal parietal cells, dysplasia cells to cancer cells till negative. CONCLUSION: Abnormal expression of APC gene occurs mainly in precancerous lesion-severe dysplasia. It is considered as an early event during gastric carcinogenesis. Detecting APC gene in gastric mucosa helps predict the trend of dyplasia to become malignant, and diagnose gastric cancer in early stage.

Adenomatous Polyposis Coli Protein↗
PubMed2000

[Comparison of effect of the mandible setbacked by SSRO and IVRO on gnathostomatic system].

OBJECTIVE: To compare the effect of the mandible setbacked by sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO) on gnathostomatic system. METHODS: 27 cases with mandibular prognathism were treated, 16 received SSRO and 11 IVRO. Their occlusal force and masticatory efficiency were measured preoperatively and at 3 and 6 months after operation. The condylar positions were assessed by radiography before surgery and at 6 months postoperatively. RESULTS: In three months postoperatively, the occlusal force and masticatory efficiency of IVRO group was decreased more than that of SSRO group. At six months postoperatively, the occlusal force and masticatory efficiency of SSRO group recovered quicker than IVRO group and better than that of before operation. In IVRO group, the occlusal force approached the preoperative level, the masticatory efficiency was better than preoperative value. 26/32 (81.2%) condyles were relatively retropositioned in SSRO group, 14/22 (63.6%) condyles were relatively forward positioned in IVRO group. CONCLUSIONS: The function recovery time after surgery was shorter in SSRO group. The masticator muscles were detached in varying degree and the bone segments healed slowly, the effect on gnathostomatic system was greater and recovery time after surgery was longer in the IVRO group.

Adult↗
PubMed2000

[Changes of myocardial tissue and plasma angiotensin II in rats with pressure overload and effect of lujiao prescription].

OBJECTIVE: To observe the changes of myocardial tissue and plasma angiotensin II in rats with pressure overload and effect of Lujiao prescription (LJP). METHODS: Left ventricular mass index (LVMI), cardiac tissue and plasma angiotensin II were measured in the rat model with myocardial hypertrophy of congestive heart failure and pressure overload by abdominal aortic constriction by radioimmunoassay. RESULTS: LVMI level in the model group was obviously higher than that of the sham group (P < 0.001), while in LJP groups (both groups of low and high dose) was lowered significantly as compared with the model group. The myocardial and plasma angiotensin II levels in the model group were obviously higher than those of the sham group (P < 0.001), while those of the LJP groups were also lowered significantly (P < 0.001). CONCLUSIONS: Cardial tissue and plasma angiotensin II in rats with myocardial hypertrophy of congestive heart failure by pressure overload were increased, and LJP could decrease them significantly. The therapeutic mechanism of LJP in treating heart failure might be related with the lowering of angiotensin II in cardial tissue and plasma so as to reduce the left ventricular hypertrophy.

Angiotensin II↗
PubMed2000

[Toxic effects of aluminum on human embryonic cerebral neurocytes in vitro studies].

OBJECTIVE: To study the toxic effect of aluminum on human embryonic cerebral neurocytes in vitro studies. METHODS: Human embryonic cerebral neurocytes were divided into three groups (control, low Al and high Al groups). The growth, development and morphology of neurocytes were observed by light and electron microscopy. The protein, DNA, lipid peroxide (LPO) contents and the activity of neuron-specific enolase (NSE) and cholinesterase (CHE) of neurocytes were detected. RESULTS: The number of viable cells in high Al group was significantly lower than that in the control group (P < 0.05). The number of swelling, degenerated and necrotic cells was significantly increased in high Al group. The DNA content and the activity of NSE and CHE of neurocytes were significantly decreased with the increase of Al concentrations (P < 0.05). The LPO content of neurocytes in the high Al group was significantly higher than that in the control group (P < 0.05). There was a positive correlation between the Al dose and LPO content of neurocytes (P < 0.05). The electron microscopy study showed that the membrane structure of cell was damaged in the high Al group and the arrangement of microtubules in the processes was disordered. CONCLUSIONS: The growth, development and function of human embryonic cerebral neurocytes was inhibited in the high Al group. The neurotoxicity of Al may be caused by lipid peroxidation and the damage of cell membrane.

Aluminum↗
PubMed2000

[Pituitary adenylate cyclase activating polypeptide ameliorates the damage and inhibits the increase of intracellular calcium concentration in cultured hippocampal neurons induced by glutamate].

Hippocampal neurons cultured from 7 to 9 d in vitro were used to observe the effect of glutamate. Treatment of glutamate for 24 h greatly decreased neuronal survival and pretreatment with pituitary adenylate cyclase activating polypeptide (PACAP) significantly attenuated hippocampal neuron death induced by glutamate. Moreover, glutamate dose-dependently increased the intracellular calcium concentration in cultured hippocampal neurons, while PACAP inhibited the increase of intracellular calcium concentration induced by glutamate. PACAP 6-38, a specific PACAP type I receptor antagonist, completely inhibited the amelioration of glutamate induced death and the decrease of intracellular calcium concentration induced by PACAP in cultured hippocampal neurons. The data suggest that PACAP has a neuroprotective effect on the hippocampal neuronal damage induced by glutamate, which is related to an inhibition of glutamate-induced increase of intracellular calcium concentration and mediated by PACAP type I receptor.

Animals↗
PubMed2000

[Tensile mechanics of mandibular condylar cartilage].

OBJECTIVE: To study the biomechanical properties of the mandibular condyle cartilage and determine its functional importance. METHODS: Eight condyle specimens of the four pig temporomandibular joints were obtained by autopsy and stored in sealed plastic bags at -20 degrees C. These pigs were healthy, aged 1 year +/- 2 months. In the coronal direction, 300 microns wide, rectangular cartilage-bone specimens were prepared on the right condyles using specified knife. In the sagittal direction, rectangular cartilage-bone specimens with the same width were obtained on the left condyles. Standard rectangular testing specimens were prepared from cartilage-bone specimens in a microtome kept at -20 degrees C (300 microns wide and 250 microns thick). The specimens were inserted in a soft-tissue uniaxial tensile test machine and immersed in a bath of Ringer's solution at room temperature. Preconditioning of the specimens was carried out prior to the uniaxial tensile experiment and the specimens were elongated to failure with the constant strain rate (0.05 mm/s). The resulting mean values were curved fitted with Fung's two-parameter (A, B) exponential stress strain equation using a nonlinear regression program. RESULTS: The data obtained showed that a typical nonlinear biomechanical behavior of the condyle cartilage. Toe-region and quasi-linear zone were obvious on the experimental stress strain relation curve. Theoretically fitted parameter A and B were 0.47 and 4.13 (coronally) and 0.60 and 4.70 (sagittally). The sagittal specimens showed greater tensile stress (2.92 MPa), tensile stiffness (9.04 MPa), energy absorption (6.02 N.mm) but less tensile strain (37.34%) than that of the coronal specimens (2.15 MPa, 6.55 MPa, 4.91 N.mm, and 41.12%). The differences were statistically significant (P < 0.05). CONCLUSION: The mandibular condyle cartilage is a kind of biophasic material which shows nonlinear viscoelastic behavior, anistrophic characteristics in biomechanical function and high ability to resist tensile stress in the longitudinal direction.

Animals↗
PubMed2000

[Pharmacodynamic effects of the extracts from Orobanche cumana].

Pharmacodynamic effects of the extracts from Orobanche cumana were studied for the first time. The result showed that it has the effects of antifatigue, facilitating immune function and an andrin-like action. It is consided that Orobanche cumana can be developed as a new medicinal resource plant.

Adjuvants, Immunologic↗
PubMed2000

[High dose intravenous immunoglobulins in treating systemic lupus erythematosus-associated thrombocytopenia].

OBJECTIVE: To study the effect of high dose intravenous immunoglobulins(IvIg) in systemic lupus erythematosus (SLE)-associated thrombocytopenia. METHODS: A case-control study was undertaken to assess the effectiveness of different therapeutic regimens (oral prednisone, IvIg, bolus methylprednisolone(MP), and IvIg plus bolus MP) in improving SLE-associated thrombocytopenia. RESULTS: For SLE-associated thrombocytopenia, IvIg, bolus MP, and IvIg plus bolus IvIg significantly shorten the time to reach a peak platelet count, which was (6.2 +/- 4.4) days, (7.3 +/- 4.9) days, and (3.8 +/- 2.4) days respectively in comparison with oral prednisone, which was (31.0 +/- 17.8) days (P< 0.01); if high dose IvIg and MP in combination, the time was also shorter than bolus MP alone (P < 0.05). The elevation of platelet count in groups receiving IvIg, bolus MP, and IvIg plus bolus MP were significantly higher than as in group receiving oral prednisone therapy(P < 0.05). CONCLUSIONS: High dose IvIg is a useful therapy in improving SLE-associated thrombocytopenia.

Adult↗
PubMed2000

[Effect of Tripterygium Wilfordii Hook T4 monomer on proliferation and interleukin-6 production of synovial fibroblasts of patients with rheumatoid arthritis].

OBJECTIVE: Tripterygium Wilfordii Hook multi-glycosides T2 has been wildly used in China in treatment of RA. T4 was abstracted from T2 and was reported much more efficient in anti-inflammatory and immune suppression than T2. This study was to investigate the effect Tripterygium Wilfordii Hook T4 monomer on proliferation and interleukin-6 production of synovial fibroblasts of patients with rheumatoid arthritis. METHODS: Synovium was obtained from patients with rheumatoid arthritis undergoing synovectomies or joint replacement. Cultures of synovial fibroblasts were established. After 3 generations, cultured synovial fibroblasts were stimulated with IL-1. Then 1.5 ng/ml, 5 ng/ml and 15 ng/ml T4 were added, and synovial fibroblasts were cultured in the presence of T4 for 48 hours. Cell proliferation was assayed using MTT method. IL-6 level of supernatant was measured by ELISA. RESULTS: Proliferation of synovial fibroblasts was inhibited by T4. The proliferation inhibition effect of T4 was dose dependent and inhibition rate was 5.18%, 10.95% and 21.37%, respectively. And T4 had no effect on IL-6 production by IL-1 stimulated synovial fibroblasts. CONCLUSIONS: T4 might control the disease activity of RA by inhibiting the proliferation of synoviocyte. And T4 might not influence the concentration of IL-6 in synovial fluid, as a central effect, since IL-6 has protective effect on articular cartilage.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2000

[IR search through Internet].

In our laboratories, we have almost had the complete Sadtler IR database, about 133,000 spectra. Based on Sadtler IR Search Master software, off-line spectrum search through internet has been set up in this work. Customers e-mail their unknown spectra as attached files to ftir2000@sina.com or ftir@microchem.org.cn. After we download the unknown spectra and search them, we will send the search reports in Microsoft Word format back to the customers within 72 hours. Please visit our web site www.microchem.org.cn to know the policy about our IR search program.

Databases, Factual↗
PubMed2000

[Determination of trace Cr in medical material progesterone by flame atomic absorption spectrophotometry].

This paper report the development of the determination of trace metal Cr in medical material progesterone by flame atomic absorption spectrophotometry. After the organic compounds are eliminated by HNO3-H2O4 to decomposite completely, the sample is determinated by FAAS. The method is convenient and the results show good precision and accuracy. The relative standard deviation was 3.0% and the rate of recovery was 98.8%.

Chromium↗
PubMed1999

Activation of T lymphocytes for adhesion and cytokine expression by toxin-conjugated anti-CD3 monoclonal antibodies.

BACKGROUND: Immunosuppressive drugs that target T cells are useful for prolonging allograft survival. The anti-CD3 immunotoxin FN18-CRM9 has been shown to effectively prolong renal allograft survival in a rhesus monkey model of transplantation. However, immunotoxin-treated monkeys showed increased levels of inflammatory cytokines and produced antibodies to donor proteins. To better understand the role of FN18-CRM9 in the production of cytokines and anti-donor antibodies in the monkey model, we examined whether this immunotoxin elicits functional responses in T cells. METHODS: Purified normal rhesus monkey T cells (>98% purity) were incubated with immunotoxin FN18-CRM9 or the unconjugated anti-CD3 monoclonal antibodies and then examined for changes in protein tyrosine phosphorylation, adhesion to fibronectin, gene expression, and proliferation in the presence or absence of anti-CD28 monoclonal antibodies (mAb) and interleukin-2. RESULTS: Immunotoxin treatment of T cells in vitro increased protein tyrosine phosphorylation, cell adhesion to the extracellular matrix, and expression of the inflammatory cytokines interferon-gamma and tumor necrosis factor-alpha. These immunotoxin effects were similar in magnitude to those induced by the unconjugated mAb. In contrast, immunotoxin-induced T cell proliferation was markedly less than that induced by the unconjugated mAb. Interestingly, the mitogenic molecules IL-2 and anti-CD28 mAb did not prevent immunotoxin-induced inhibition of cell proliferation. CONCLUSIONS: The activation of T cells for protein phosphorylation, adhesion, and cytokine expression strongly suggests that the actions of FN18-CRM9 in vivo are not limited to the inhibition of protein synthesis.

Animals↗
PubMed1999

Concurrent deregulation of gelsolin and cyclin D1 in the majority of human and rodent breast cancers.

Decreased gelsolin and increased cyclin D1 are among the most common defects found in human and rodent breast cancers. Our purpose was to determine the frequency of concurrence of these 2 alterations in this malignancy. Our results demonstrate that gelsolin protein and mRNA were significantly reduced in 80-100% of rodent mammary carcinomas that developed spontaneously, following oncogene introduction, or after treatment with viral, chemical or hormonal agents. The reduction in gelsolin most likely occurs during the transition from preneoplasia to carcinoma because hyperplasias had normal levels of gelsolin whereas microtumors had reduced expression. Southern analysis revealed no major mutations in the gelsolin gene of tumors with low expression. Cyclin D1 mRNA was increased in 50-100% of these rodent mammary tumors, although the cyclin D1 gene was not amplified. By nuclear runon assay, downregulation of gelsolin in both human and mouse mammary cancer cells involved diminished transcription and, conversely, human breast cancer cells expressing high levels of cyclin D1 had increased initiation of cyclin D1 transcription compared with cyclin D1 low expressors. Thus, alteration in the rate of transcription appears to be an important factor underlying the dysfunction of these genes. According to our data, concurrent deregulation of gelsolin and cyclin D1 is highly prevalent among breast cancers of humans and rodents, with both defects present in 89% of the neoplasms analyzed in this study. In fact, most tumors in every rodent model of mammary tumorigenesis examined had the 2 alterations.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1999

Synthesis and antimalarial activity of 11 dispiro-1,2,4,5-tetraoxane analogues of WR 148999. 7,8,15,16-Tetraoxadispiro[5.2.5.2]hexadecanes substituted at the 1 and 10 positions with unsaturated and polar functional groups.

Eleven novel dispiro-1,2,4,5-tetraoxanes 3 bearing unsaturated and polar functional groups were designed to enhance the oral antimalarial activity of the prototype tetraoxane 2 (WR 148999). With the exception of 3g and 3h, tetraoxanes 3 were available via the peroxidation of corresponding cyclohexanone derivatives in H2SO4/CH3CN. Tetraoxanes 3g and 3h were prepared by hydrolysis of ester tetraoxanes 3e and 3i, respectively. Five of the 11 tetraoxanes were inactive, but six tetraoxanes had IC50 values of 6-26 nM against the K1 and NF54 strains of Plasmodium falciparum compared to corresponding IC50 values of 28 and 39 nM for 2, and 10 and 12 nM for artemisinin (1). Ester tetraoxane 3e was the most active in vitro, some 2-fold more potent than 1. However, none of the six tetraoxanes active in vitro were as effective as either 1 or 2 in vivo; at single doses of 100 mg/kg most possessed little to no vivo activity in mice infected with Plasmodium berghei. Unsaturated tetraoxane 3a was uniquely more active when administered per os (po) than subcutan (sc). For this series of tetraoxanes, the discrepancy between vitro and vivo activities underscores the limitations of conclusions drawn solely from in vitro antimalarial data and illustrates a practical benefit of complementary single-dose in vivo antimalarial screens.

Administration, Oral↗