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Biomedical subjects

D Wang

Publications and source records attributed to D Wang.

At least 631 records · Page 35Linked to original sources
PubMed1998

[Distraction osteogenesis for the correction of severe unilateral posterior lockbite: preliminary report].

The aim of this study was to promote an effective approach, which was surgically-assisted buccal mandibular corticotomy in the lockbite side to rapidly expand mandibular arch to correct unilateral posterior lockbite using the principle of the distraction osteogenesis. The typical subject was a 16-year-old patient with unilateral posterior lockbite. The orthodontic treatment had been done before the surgery. After the surgery, reciprocal elastic traction between upper and lower arch were used immediately in the lockbite side. The results demonstrated that unilateral posterior lockbite could be effectively corrected with unilateral buccal mandibular corticotomy and rapid mandibular expansion, and the stability appeared satisfactory. This article also discussed the indications of the approach and processes of treatment.

Adolescent↗
PubMed1998

[The effects of TGF-beta on the proliferation and differentiation of human osteoblast-like cells].

Osteoblast-like cells were isolated from embryonic human calvarium with modified enzyme digestion method. TGF-beta which is believed having biological effects on bone cells was added into the culture medium with separate concentrations. The incorporation of 3H-TdR, 3H-Proline of osteoblast-like cells and alkaline phosphatase(ALP) content of the cells were tested to study the effects of the TGF-beta on the proliferation of osteoblasts. The results showed that TGF-beta increased ALP activity and the synthesis of collagen, and the cell proliferation was inhibited. It affected the proliferation and differentiation of osteoblast-like cells with the best 1 ng/ml among four concentration of 0.01-10 ng/ml. These findings suggested that function of TGF-beta might be modified by other local growth factors.

Alkaline Phosphatase↗
PubMed1998

[The effects of IGF-II on the proliferation and differentiation of human osteoblast-like cells].

Biological regulatory mechanism which supports bone cell development within the context of proliferation/differentiation relationship serves as a viable basis for addressing skeletal disorders and provides experiment and theoretic basis for selection and utilization of growth factors to reconstruct bone defect. Osteoblast-like cells isolated from human calvarium were used in this study. IGF-II were investigated by adding in the culture medium with different concentration. The results showed that IGF-II stimulated DNA, collagen synthesis and ALP activity of human osteoblast-like cells. Its effects were strong for proliferation and differentiation of osteoblast cells, when 10 ng/ml of four different concentrations (0.1, 1, 10 and 100 ng/ml) were used. IGF-II was proved to be important factor in bone regeneration.

Alkaline Phosphatase↗
PubMed1998

[An experimental study of expediting the early attachment of human gingival epithelial cells to titanium with laminin].

Using in vitro culture model, the attachment of human gingival epithelial cells to laminin-coated pure titanium was studied. The average numbers of attached cells on different surface of titanium with or without laminin were calculated under catoptric fluorescent microscope and were statistically analyzed with factorial design. The results showed that Laminin could expedite the early attachment of human gingival epithelial cells to titanium.

Cell Adhesion↗
PubMed1998

[The effect of internal irradiotherapy with 32P glass microspheres on tumor vasculature in mouse sarcoma 180].

In order to investigate the effect of internal irradiotherapy on tumor microvasculature, the vascular changes of tumor S180 following internal irradiotherapy with 32P glass microspheres were observed microscopically with vessel casts of resin perfusion and ink perfusion. The results showed that the microvessels expanded with the endothelial cells swelling and the amount of microvessels and new vessels decreased, which led to peritumoral vascular density descended. It suggests that internal irradiotherapy destroying the tumor microvasculature as external irradiation is an important influence on the efficiency of internal irradiotherapy.

Animals↗
PubMed1998

[Quantitative study of catecholamines in normal human dental pulp].

The purpose of this report was to study quantitatively the levels of catecholamines in human dental pulp by high-performance liquid chromatography (HPLC). 10 healthy teeth were selected from the extractions due to orthodontic reasons. The pulp of the teeth were obtained immediately after the extraction and samples were analyzed by means of HPLC for levels of dopamine, epinephrine and norepinephrine. The result showed that the concentration of norepinephrine in human dental pulp was 23.47 +/- 0.52 micrograms/g pulp tissue and dopamine was 19.17 +/- 1.03 micrograms/g pulp tissue.

Catecholamines↗
PubMed1998

[Cloning and sequencing of the Chinese bovine prion protein (PrPC) gene].

The total DNA was isolated from lymphocyte of peripheral blood of Chinese cattle. The PrPC gene was amplified by polymerase chain reaction, using two primers. It was then cloned into pGEM-T Easy Vector. The result of DNA sequencing was indicated that the 795 bp amplified fragment contains the entire PrPC coding sequence, which has no intron and is same as the published gene sequence.

Amino Acid Sequence↗
PubMed1998

[Hemorheologic change after strong blood flow disturbance caused by gunshot and its influence on the prognosis of the wounded animals].

Three types of experimental models were used in this study: 1. Both thighs of dogs were wounded by 5.56 mm bullet. 2. Femoral artery and vein were tied at the time of wounding. 3. Shock caused by simply bleeding the dogs' femoral arteries. We observed the characteristics of change hemorheology and analyzed its effects on the wounded dogs. The results showed that strong blood flow disturbances always brought about hemorheologic changes such as rapidly increased blood viscosity and red cell's aggregation index and the simultaneous phenomenon of blood concentration. These may be related to extensive endothelium injury and destruction of a number of blood cells caused by disturbance wave. The above change may give rise to abnormality of microcirculation and disturbance of matter transmission; in that sense, it may provide the physiopathologic basis for the occurrence and development of the complication.

Animals↗
PubMed1998

[Tetracycline tracing of artificial bone composite with high biological induction in repairing bone defect].

The tetracycline tracing method was adopted to study the new bone formation at the early stage of two different composite artificial bones (HA-bBMP-Co and HA-Co)in repairing segmental bone defect in 8 rabbits. The results indicated that from the early stage even just one week after implantation, HA-bBMP-Co acted much faster than HA-Co did in inducing new bone formation, suggesting that HA-bBMP-Co be of good quality in ferms of histo-compatibility and osteoinduction.

Animals↗
PubMed1998

[Study of the inclusion compound of rutin with beta-cyclodextrin].

In order to improve the solubility of Rutin in aqueous solution and the stability, the inclusion compound of Rutin with beta-CD was manufacted by saturated aqueous solution method. The formation of the inclusion compound was confirmed by IR spectroscopy and differential scauning calorimetry. The content of Rutin in inclusion compound was determined by UV. The results indicated that the inclusion compound of Rutin with beta-CD was formed. Quantitative analysis demmonstrated that the molecular ratio of Rutin to beta-CD in the complex was 1:1 with the inclusion constant of 283.79 L/mol at 30 degrees C. The dissolubility of Rutin in water has added to 643.19 mg/L (20 degrees C).

Biological Availability↗
PubMed1998

[Study on the determination of trace mercury in foods by circulating enrichment-cold vapour atomic absorption spectrometry].

The determination of trace mercury using the self-developed circulating enrichment apparatus with cold vapour atomic absorption spectrometry was investigated. Various experimental conditions were discussed and optimized. The effect of interferences was examined. The developed method is sensitive, accurate, simple and available and has already been used in the analysis of various kinds of food samples and national standard reference materials, and the results obtained were satisfactory.

Cold Temperature↗
PubMed1998

The liver isoform of carnitine palmitoyltransferase I is activated in neonatal rat cardiac myocytes by hypoxia.

Fatty acids are the preferred substrate of ischemic, reperfused myocardium and may account for the decreased cardiac efficiency during aerobic recovery. Neonatal cardiac myocytes in culture respond to hypoxia/serum- and glucose-free medium by a slow decline in ATP which reverses upon oxygenation. This model was employed to examine whether carnitine palmitoyltransferase I (CPT-I) modulates high rates of beta-oxidation following oxygen deprivation. After 5 h of hypoxia, ATP levels decline to 30% control values and CPT-I activity is significantly stimulated in hypoxic myocytes with no alteration in cellular carnitine content or in the release of the mitochondrial matrix marker, citrate synthase. This stimulation was attributed to an increase in the affinity of hypoxic CPT-I for carnitine, suggesting that the liver CPT-I isoform is more dominant following hypoxia. However, there was no alteration in hypoxic CPT-I inhibition by malonyl-CoA. DNP-etomoxiryl-CoA, a specific inhibitor of the liver CPT-I isoform, uncovered identical Michaelis kinetics of the muscle isoform in control and hypoxic myocytes with activation of the liver isoform. Northern blotting did not reveal any change in the relative abundance of mRNA for the liver vs. the muscle CPT-I isoforms. The tyrosine phosphatase inhibitor, pervanadate, reversed the hypoxia-induced activation of CPT-I and returned the affinity of cardiac CPT-I for carnitine to control. Reoxygenation was also associated with a return of CPT-I activity to control levels. The data demonstrate that CPT-I is activated upon ATP depletion. Lower enzyme activities are present in control and reoxygenated cells where ATP is abundant or when phosphatases are inhibited. This is the first suggestion that phosphorylation may modulate the activity of the liver CPT-I isoform in heart.

Adenosine Triphosphate↗
PubMed1998

Effects of radiation on wound healing.

The pathological changes of radiation on wound healing in rats were observed by macroscopic, microscopic, and electronmicroscopic examination and detection of collagen types. We found that the wound healing process was obviously delayed by irradiation. First, the early phase inflammatory response was severely inhibited. In particular, the number of infiltrating macrophages and neutrophils was decreased, blood vessels were injured, and hemorrhage was evident. Second, the formation and maturation of granulation tissue were slowed down, fibroblasts were injured, and transcription of types and collagen mRNAs and synthesis and secretion of collagen were reduced. Finally, the reepithelialization process was delayed and the healing time was prolonged.

Animals↗
PubMed1998

Overexpression of MDM2, p53, and NCAM proteins in human radiation-induced skin ulcers.

Using immunohistochemistry, we studied the overexpression of MDM2, p53, and NCAM proteins in human radiation-induced skin ulcers. We found that the positive rate of overexpression of MDM2, p53, and NCAM was 36%, 8%, and 32%, respectively. The overexpression of MDM2 protein was mainly observed in the nuclei of fibroblasts in the deeper part of the ulcer; that of p53 protein was in the nuclei of the epidermis and in the cytoplasm of fibroblasts and endothelial cells, whereas that of NCAM was located in the cytoplasm of squamous epithelial cells of the epidermis and in fibroblasts, fibrocytes, endothelial cells, and leiomyocytes in the media of arteriolar walls. The overexpression of MDM2, p53, and NCAM may be related to the poor healing of radiation-induced skin ulcers and the cancer transformation.

Gene Expression↗