Biomedical subjects

D Wang

Publications and source records attributed to D Wang.

At least 253 records · Page 14Linked to original sources

PubMed2001

Changes in the temporomandibular joint after mandibular lengthening with different rates of distraction.

This study assessed the changes in the condyle after mandibular lengthening with 2 different rates of distraction (1 mm/day and 2 mm/day). Unilateral mandibular distraction was performed in 8 young adult goats. The animals were sacrificed 8 weeks after the completion of distraction, and the temporomandibular joint (TMJ) specimens were harvested and processed for histologic examination and histomorphometric analysis. Adaptive changes in the condyle were observed in the goats distracted at a rate of 1 mm/day, whereas degenerative alterations were found in those distracted at a rate of 2 mm/day. This study suggests that the TMJ is able to withstand the impact of distraction at a rate of 1 mm/day, but more rapid distraction may induce degeneration in the condylar cartilage.

Animals↗

PubMed2001

[Impact of interstitial irradiation with 32P glass microspheres on cellular apoptosis of mice with the solid tumor S180].

OBJECTIVE: The aim of this study is to observe apoptotic changes of tumor cells in mice with the solid tumor S180 after interstitial irradiation with 32P glass microspheres. METHODS: Twenty mice with solid tumor S180 were divided into four groups. The control group was given normal saline. The experimental groups were given different doses of 32P glass microspheres (50, 150, 450uci per mouse) using interstitial implant. The terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) method was used to determine the apoptotic cells. RESULTS: The mean values of the apoptotic indexes of these groups were respectively 0.39, 0.41, 0.59 and 0.95. The apoptotic indexes of the second and the third experimental groups were significantly higher than that of the control group (P < 0.05). CONCLUSION: The interstitial irradiation with 32P glass microspheres can enhance the activity of apoptotic cells of solid tumor S180, and the effect is dose-dependent.

Animals↗

PubMed2001

[Apoptosis induced by interstitial irradiation with 32P glass microspheres combination with hyperthermia in mouse solid tumor S180].

OBJECTIVE: The aim of this study was to observe the changes of tumor cell apoptosis after interstitial irradiation combination with the hyperthermia treatment. METHODS: Twenty mice with solid tumor S180 were divided into four groups, including a control group which was given normal saline, and three experimental groups which were respectively applied with a hyperthermia treatment (bath water), interstitial irradiation with 32P glass microspheres, and the combined treatment of hyperthermia and interstitial irradiation. The terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) method was used to determine the final apoptotic cells. RESULTS: The mean values of apoptotic indexes of these four groups were respectively 0.39, 0.53, 0.59 and 0.91. The apoptotic indexes of these experimental groups were significantly higher than that of the control group (P < 0.05). The apoptotic index of the combined treatment group was significantly higher than those of the hyperthermia group and the interstitial irradiation group (P < 0.05). CONCLUSION: Both the interstitial irradiated with 32P glass microspheres and hyperthermia (bath water) can induce the apoptosis of mouse solid tumor S180. It seems that there is a synergistic induction of apoptosis between interstitial irradiation and hyperthermia.

Animals↗

PubMed2001

[Ultrastructural and Ca/P changes of the regenerated bone after mandibular distraction in goats].

OBJECTIVE: The aim of this study was to examine the ultra structural and the changes of Ca/P elements of the new bone resulting from mandibular distraction osteogenesis. METHODS: Bilateral mandibular osteotomies were performed in six goats. The mandibles in all animals were lengthened 10 mm using a custom made distracter. Each 2 goats were sacrificed respectively at 2, 4 and 8 weeks after completion of distraction. The distracted callus were harvested and processed for SEM evaluation and Ca/P ratio analysis. RESULTS: The newly generated bone in distraction gap was confirmed by SEM examination, and the contents of Ca, P were found to be elevated with the maturity of distracted callus. CONCLUSION: This study suggested that newly formed bone by mandibular distraction osteogenesis in goats could be remodeled to normal bone.

Animals↗

PubMed2001

[Effects of XW630 on mechanical properties and trabecular structure parameters of bone tissue in ovariectomized rats].

OBJECTIVE: The study aimed at investigating the effects of a new anti-osteoporotic drug, XW630 on promoting the osteogenic activity of bone tissue in ovariectomized rats. METHODS: Thirty-six female SD rats, three months old, were randomly divided into four groups: sham-operated group (sham), the ovariectomized group (OVX), the esterone-therapy group (OVX + CFT) and the XW630-therapy group (OVX + XW630). Three rats in each group were killed on the 30th, 60th, and 90th day after the operation. The femur of one side was taken for the three-point bending resistance test, and the bilateral tibias were taken for the HE stain and scanning electronic microscopy (SEM) examination. RESULTS: The HE and SEM results indicated that the bone loss appeared in the OVX group 30 days after the operation, which lasted for the whole observing period. While after application of ester-one and XW630, there were different degrees of bone repairing around the trabeculae, and the osteogenic activity was obviously active in the XW630 group than that in the esterone group. During the experimental period, the three-point bending resistance of the OVX group gradually decreased and there was a significant difference compared with that of the sham group (P < 0.01), while the three-point bending resistance of the two therapy group gradually increased and there was significant difference between the OVX group and the XW630 group (P < 0.05 and P < 0.01). CONCLUSION: XW630 can effectively promote osteogenic action and prevent osteoporostic fracture in ovariectomized rats.

Animals↗

PubMed2001

[Regulation of XW630 on TGF-beta 1 and collagen I gene expression in osteoblasts].

OBJECTIVE: The purpose of this part of study was to investigate the mechanism of a new anti-osteoporotic drug, XW630 on promoting osteogenic activity. METHODS: Total RNA were isolated from osteoblasts of the mice after the reaction with XW630 in 24 and 72 hours, that were hybridized with the extracted and digoxigenin-labeled TGF-beta 1 and the collagen I cDNA probes. RESULTS: XW630 significantly promoted TGF-beta 1 and collagen I gene expression in osteoblasts, and this drug was superior than other two kinds of estrogen in promoting osteogenic activity (P < 0.05). CONCLUSION: XW630 promote osteogenic activity of osteoblasts, probably by enhancing the mRNA expression of TGF-beta 1 and collagen I.

Animals↗

PubMed2001

[Changes of soft tissue profile in operated unilateral cleft lip and palate patients after maxillary protraction].

OBJECTIVE: The aim of this study is to investigate effects of maxillary protraction on soft tissue profile in operated operated unilateral cleft lip and palate (UCLP) patients. METHODS: A total of 10 growing UCLP patients (male 7, female 3), age from 8.2 to 12 years old (Average: 10.4 years old), were selected to be treated with maxillary protraction using head gear-chin cap-long hook protraction appliance. The appliance was worn 12-14 hours per day, and the protraction force was 400-500 g each side. The protraction direction was forward and slightly downward. The treatment period was 4.7 months (Average: 5.8 months). Cephalometrics were taken before and after treatment. The changes of soft-tissue profile were studied using the computer-aid X-ray cephalometric analysis. RESULTS: After protraction, the points of Prn, Sn and Ls moved forward significantly. The distance from points Ls to E plane changed significantly from 0.46 mm before treatment to 1.18 mm after treatment. The angle G-Prn-Pg' decreased significantly, and G-Sn-Pg' changed significantly from -0.30 before treatment to 6.260 after treatment. The anterior-posterior position of mandible and lower lip did not change significantly, the changes of angles Cm-Sn-Ls, A'ls/SiLi had no statistical significance. The results indicated that maxillary protraction could make maxilla and upper lip move forward, and the convexity of soft tissue profile improve significantly. CONCLUSION: Maxillary protraction is an effective way to improve the facial deformity of operated UCLP patients. UCLP patients should have early interrupted treatment.

Cephalometry↗

PubMed2001

[Study on analysis of trace phenol in small amount of aqueous sample by liquid-liquid micro-extraction and gas chromatography].

A method for the liquid-liquid micro-extraction and gas chromatographic analysis of trace phenol in small amount of aqueous sample has been developed. The influences of acid and salts on recovery rate of phenol were examined. And, the influences of injection speeds and the conditions of silica wool in injection port on the quantitation precision were tested. With a direct injection port, an FID and a DB-1 capillary column of wide bore, a detection limit of 1 microgram.L-1 can be obtained employing 8 mL water sample, 160 microL ethyl acetate and 3.5 g ammonium sulfate. The added recoveries were in the range of 95.0%-98.5%. The relative standard deviations were in the range of 2.8%-3.3%. This method is simple, convenient, rapid, accurate and practical.

Chromatography, Gas↗

PubMed2001

[Isolation of a development revertant of Myxococus Xamthus].

fruA::Tc omega 5 is a development deficient strain of M. Xamthus. Transposon TnV was used to randomly mutagenize various sites of fruA::Tc omega 5 chromosome. Fruiting body formation was restored in one TnV insertion mutant, designated XM1206. The TnV-inserted DNA fragment from XM1206 chromosome was cloned, which may be served as a probe to isolate the corresponding allele from wild-type strain.

Bacterial Proteins↗

PubMed2001

Association between low-density lipoprotein receptor-related protein gene, butyrylcholinesterase gene and Alzheimer' s disease in Chinese.

OBJECTIVE: To research the relations between low-density lipoprotein receptor-related protein gene (LRP) polymorphism, butyrylcholinesterase gene (BchE) polymorphism and Alzheimer's disease (AD) in Chinese. METHODS: The gene polymorphisms of LRP and BchE were genotyped in 38 AD cases and 40 controls with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods. AD groups were classified according to the LRP C/C genotype and compared with matched controls. RESULTS: AD group had higher frequencies of C/C homozygote (81.69% vs 60.0%, P < 0.05) and of C allele (89.5% vs 76.3%, P < 0.05), with no significant difference between any of these LRP genotypes classified AD groups and their respective control groups. CONCLUSIONS: A positive correlation was found between LRP gene polymorphism and AD, but not between BchE gene polymorphism and AD in Chinese AD cases.

Aged↗

PubMed2001

[The role of neuroimmunoregulation mobilized by enhancing immunologic function via hou hai acupoint antigen injection].

OBJECTIVE: To study the mechanism of neuroimmunoregulation which is triggered by enhancing immunologic function via Hou Hai acupoint antigen injection. METHODS: Immunohistochemical method, immunofluorometric method and RT-PCR were used to examine the different distribution of cytokine immunopositive cells in the brain and expression of cytokines in the spleen of the human IgG sensitized rats received acupoint, subcutaneous and normal rats antigen injections. RESULTS: In the areas of lateral hypothalamic nucleus (LH) and amygdaloid nuclear complex (AA), the distribution of cytokines immunopositive cells with acupoint injection group was significantly increased more than that in the subcutaneous injection group. But the expression of cytokines immunopositive cells both by the acupoint injection and the subcutaneous injection groups reached their peak value in similar time. Double-labelling results showed that the cytokine immunopositive cells were neurons. In the spleens, the expressions of cytokines, IL-2 and IFN, were significantly increased by acupoint injection more than subcutaneous injection. CONCLUSIONS: The time course of neuroimmunoregulation is similar in the immunized rats via both acupoint injection and subcutaneous injection of antigens. But the activity of neuroimmunoregulation is not the same in acupoint and subcutaneous injection groups. Neurons of the LH and AA are the main source of the neuroimmunomodulators. The effect of enhancing immunologic function via Hou Hai acupoint injection is may be more efficient to mobilize the activity of neuroimmunoregulation of immune-associated brain region than modulation of the immune system.

Acupuncture Points↗

PubMed2001

[Simultaneous determination of aspirin, phenacetin and caffeine in compound APC by derivative ratio UV adsorption spectrum method].

The principle of derivative spectrum is described, which is based on the simultaneous use of the first derivative of ratio spectra and measurements of zero-crossing wavelengths. The method can be used to analyze one of three components in ternary mixture and eliminate the interference of others. This method is used to determine the ternary mixture of aspirin, phenacetin and caffeine in APC simultaneous with satisfactory results. The regression coefficient is higher than 0.9992, the relative standard derivatives (RSD) is less than 3.2%, the recovery is between 93.3%-106.3%.

Aspirin↗

PubMed2001

[Analysis of the lineshape of laser frequency modulation].

In this paper, we analyze the dependence of the output signal spectral lineshape and intensity on the modulation, waveform and modulation index in first- and second-harmonic detection of triangle modulation, square demodulation and saw modulation square demodulation. The signal lineshape in the case of saw modulation, square demodulation is quite different from, whereas the signal lineshape in the case of triangle modulation, square demodulation is similar to that in traditional sine modulation, sine demodulation. Experiments of tunable IR laser frequency modulation absorption spectrum of methane are also done to verify the theoretical analysis. Then we reach a conclusion; the lineshape and intensity of frequency modulation spectrum can be influenced by modulation waveform, demodulation waveform and modulation index. Calculation results can be used to choose better experimental parameters and optimize experimental designs.

Algorithms↗

PubMed2001

[FTIR study of transition metal 2-acrylamido-2-methyl-1-propanesulfonates].

Compounds of transition metal ion (Cu2+, Co2+, Ni2+) 2-acrylamidomethyl-2-methyl-1-propanesulfonates were studied by FTIR and X-ray powder diffraction techniques. The FTIR spectra of Co and Ni compound are similar but are different from that of Cu compound. The results of X-ray diffraction indicated that the crystal structure of Co and Ni compound are different.

Acrylamides↗

PubMed2001

[Study on extraction process of aqueous part of radix Salvia miltiorrhiza].

OBJECTIVE: To find out the optimum extraction process for total salvianolic acid part of radix Salviae miltiorrhizae. METHOD: The extraction process was studied by orthogonal design with the danshen su content determined by RP-HPLC as index. RESULT: A3B3C2D1 is the best extraction condition of aqueous part from radix Salvia miltiorrhiza. CONCLUSION: This extraction process shows total salvianolic acid has high content and good stability.

Chemistry, Pharmaceutical↗

PubMed2000

Skeletor, a novel chromosomal protein that redistributes during mitosis provides evidence for the formation of a spindle matrix.

A spindle matrix has been proposed to help organize and stabilize the microtubule spindle during mitosis, though molecular evidence corroborating its existence has been elusive. In Drosophila, we have cloned and characterized a novel nuclear protein, skeletor, that we propose is part of a macromolecular complex forming such a spindle matrix. Skeletor antibody staining shows that skeletor is associated with the chromosomes at interphase, but redistributes into a true fusiform spindle structure at prophase, which precedes microtubule spindle formation. During metaphase, the spindle, defined by skeletor antibody labeling, and the microtubule spindles are coaligned. We find that the skeletor-defined spindle maintains its fusiform spindle structure from end to end across the metaphase plate during anaphase when the chromosomes segregate. Consequently, the properties of the skeletor-defined spindle make it an ideal substrate for providing structural support stabilizing microtubules and counterbalancing force production. Furthermore, skeletor metaphase spindles persist in the absence of microtubule spindles, strongly implying that the existence of the skeletor-defined spindle does not require polymerized microtubules. Thus, the identification and characterization of skeletor represents the first direct molecular evidence for the existence of a complete spindle matrix that forms within the nucleus before microtubule spindle formation.

Active Transport, Cell Nucleus↗

PubMed2000

Identification of Edg1 receptor residues that recognize sphingosine 1-phosphate.

Originating from its DNA sequence, a computational model of the Edg1 receptor has been developed that predicts critical interactions with its ligand, sphingosine 1-phosphate. The basic amino acids Arg(120) and Arg(292) ion pair with the phosphate, whereas the acidic Glu(121) residue ion pairs with the ammonium moiety of sphingosine 1-phosphate. The requirement of these interactions for specific ligand recognition has been confirmed through examination of site-directed mutants by radioligand binding, ligand-induced [(35)S]GTPgammaS binding, and receptor internalization assays. These ion-pairing interactions explain the ligand specificity of the Edg1 receptor and provide insight into ligand specificity differences within the Edg receptor family. This computational map of the ligand binding pocket provides information necessary for understanding the molecular pharmacology of this receptor, thus underlining the potential of the computational method in predicting ligand-receptor interactions.

Amino Acid Sequence↗

PubMed2000

Tetraethylammonium potentiates the activity of muscarinic potassium channels in guinea-pig atrial myocytes.

The modulation of native muscarinic potassium channels (KACh) by tetraethylammonium (TEA) was studied at 35 degrees C in cell-free patches from acutely dissociated guinea-pig atrial myocytes. The channels were identified unambiguously by their conductance, inward rectification, rapid gating kinetics and pharmacological responses to muscarinic agonists and GTPgammaS. Addition of 5 mM TEA to the cytoplasmic side of the patches almost doubled the open probability of KACh channels that had been activated maximally by GTPgammaS. In contrast even 30 mM TEA did not significantly potentiate the response to carbachol in whole-cell recordings. Unlike GTPgammaS, TEA alone did not activate KACh channels de novo, but in patches that showed spontaneous KACh activity, 5 mM TEA increased channel open probability fourfold in the absence of added sodium, ATP or guanine nucleotides. Furthermore, the effect of TEA was not blocked by 10 uM atropine or by 1 mM GDPbetaS, and subsequent addition of 0.1 mM GTPgammaS did not stimulate channel activity further in the presence of TEA. Phosphatidylinositol 4,5-bisphosphate (PIP2) also stimulates KACh channels under these conditions, but the kinetics of gating differ from channels stimulated by either TEA or GTP, which are very similar to one another. The effects of TEA were not mimicked by tetramethyl- or tetrapentylammonium or by sodium or spermine, and TEA did not potentiate the activity of other inwardly rectifying potassium (KATP) channels in patches from cardiac myocytes. We consider the possibility that TEA is mimicking the effect of an unidentified cellular factor, not sodium or PIP2, which normally occupies the TEA site on KACh channel proteins but which diffuses away when the patch is excised.

Acetylcholine↗