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Biomedical subjects

G Dang

Publications and source records attributed to G Dang.

At least 19 recordsLinked to original sources
PubMed2003

Cbfa1/osf2 transduced bone marrow stromal cells facilitate bone formation in vitro and in vivo.

It has been well established that core binding factor a-1/osteoblast-specific factor-2 (cbfa1/osf2) is a key regulator of osteoblast differentiation and function, however, it is not known whether it can induce bone formation in vitro and in vivo. To investigate the effect of cbfa1/osf2 on bone formation, we used a recombinant adenoviral vector carrying the mouse cbfa1/osf2 gene to transduce primary cultured bone marrow stromal cells (MSCs) of BALB/c mice. We found that Ad-cbfa1/osf2-transduced MSCs produced cbfa1/osf2 protein and differentiated into osteoblast-like cells. The transduced MSCs had increased alkaline phosphatase activity, increased expression of osteocalcin, osteopontin and bone sialoprotein, and increased matrix mineralization in vitro. To observe the induction of bone formation in vivo, MSCs transduced with Ad-cbfa1/osf2 were transplanted into a 5 mm diameter critical-sized skull defect in BALB/c mice, with type I collagen as scaffolding material. Healing of the defect in treatment and control groups was examined grossly and histologically at four weeks. Skull defects transplanted with Ad-cbfa1/osf2-transduced MSCs had an average of 85% osseous closure at four weeks. Control groups in which the defects were not treated (group 1), treated with collagen only (group 2), or treated with collagen and nontransduced MSCs (group 3) showed little or no osseous healing. These studies indicate that cbfa1/osf2 can induce osteoblast differentiation and bone formation both in vitro and in vivo, suggesting that MSCs transduced with the cbfa1/osf2 gene may be useful in treating bone defects.

Animals↗
PubMed2001

[Effect of sequential application of calcitonin and parathyroid hormone on bone remodeling process, an experimental research].

OBJECTIVE: To investigate the effect of sequential application of calcitonin and parathyroid hormone (PTH) on bone remodeling process. METHODS: Twelve female rats were divided equally into 2 groups: experimental group and control group. 1 U/100 g of calcitonin was injected intramuscularly to 6 rats for two days, and rrPTH in dosage of 30 micrograms was injected intramuscularly in the fourth and fifth days. At the sixth day their lumbar vertebral bodies were resected. Undecalcified and decalcified bone sections were made to be observed by optical microscopy and electronic microscopy. Bone histomorphological parameters were measured. Normal saline and solvent of the same volume were injected intramuscularly to the controls. RESULTS: The OS/BS (%), O. Th (micron), N.Ob.S (cell/mm), and Vos/TV (%) were 19.9% +/- 6.2%, 3.4 microns +/- 0.4 micron, 37.6 cells/mm +/- 4.6 cells/mm, and 1.8% +/- 0.6% respectively in the experimental group, significantly higher than those in the control group (P < 0.05). After the PTH administration, more and plumper osteoblasts were observed. They were rich in rough endoplasmic reticulum, mitochondria, and Golgi apparatus. CONCLUSION: Sequential application of calcitonin and parathyroid hormone obviously promotes the bone formation process. Both sites of bone remodeling formation and sites of bone modeling formation, especially the latter, increase.

Animals↗
PubMed2000

[Radiographic studies of cervical spine motion range in normal Chinese subjects with computer-assisted image analysis: full flexion and extension].

OBJECTIVES: To study the degenerative regularity of normal Chinese cervical spine by observing the motion range of full cervical flexion and extension, and to provide evidences for further investigation of cervical segmental instability. METHODS: 764 X-ray plain films of full cervical flexion and extension in 382 normal Chinese subjects (214 were male and 168 female) were investigated using self-designed cervical X-ray image analysis system. The subjects within the same sex group were divided into three groups according to the age: group A (20 years to 39 years), group B (40 years to 59 years) and group C (60 years to 76 years). During the full cervical flexion and extension motion, total intervertebral motion range (from C(2) - C(3) to C(6) - C(7)) and intervertebral motion range at each level were major parameters. RESULTS: The range of total intervertebral motion showed much greater mobility in group A than in group B and group C (P < 0.01) but no statistically significant difference between group B and group C (P > 0.05). The range of intervertebral motion was maximal at C(5) - C(6) in group A. The place of maximal motion shifted to the C(4) - C(5) in both group B and group C. C(2) - C(3) showed minimal mobility in all three groups. There was no statistically significant difference (P > 0.05) between male and female. CONCLUSIONS: The motion range and degenerative regularity of normal Chinese cervical spine were similar in either sex. The range of total intervertebral motion (from C(2) - C(3) to C(6) - C(7)) had a tendency to decrease rapidly and then became steady with age. For the range of intervertebral motion, the place of maximal motion shifted to the higher level with age from C(5) - C(6) in group A to C(4) - C(5) in group B and group C.

Adult↗
PubMed2000

[Influence of solid thoracolumbar kyphosis on lumbar spine and surgical treatment].

OBJECTIVE: To investigate the influence of solid thoracolumbar kyphosis on the lumbar spine and surgical treatment. METHODS: 14 had solid kyphosis of the thoracolumbar spine. Cobb angle of kyphosis of the thoracolumbar spine and lordosis between L(2)/S(1), L(2)/L(5), L(2)/L(3), L(3)/L(4), L(4)/L(5), L(5)/S(1) pre- and post-osteotomy was measured respectively, and the amount of vertebrae slipped over 3mm was recorded. The results were compared with those of the normal group respectively. RESULTS: The Cobb angles of lordosis between L(2)/S(1), L(2)/L(5), L(2)/L(3), L(3)/L(4), L(4)/L(5), L(5)/S(1) in the deformity group were increased significantly compared with those that of the normal group respectively; obvious changes in percentage occurred in the segment between L(2)/L(3) and L(3)/L(4). Over lordosis of the lumbar spine was greatly corrected postosteotomy of the thoracolumbar spine, it was still significantly different compared with that of the normal group. In 9 patients with retrolisthesis of 20 vertebrae, 70% occurred in L(2) and L(3) vertebrae. The amount of retrolisthesis of vertebrae decreased to 3 in two patients. No retrolisthesis of vertebra was seen in the normal group. Single-stage procedures combined with anterior releasing and posterior osteotomy through facet joints for kyphosis of the thoracolumbar spine showed a correction. rate of 85.7%, but single-stage osteotomy through the posterior vertebra showed a correction rate of 60.7%. Seven of 8 patients who had had seriously back pain complained of no pain or slight backache after operation. 40% of the patients showed functional improvement in the sphincter of the urinary bladder and anus. 50% of the patients had improvement in muscle strength. CONCLUSIONS: Kyphosis of the thoracolumbar spine may result in over lordosis of the lumbar spine and retrolisthesis of vertebrae, which are obvious in the upper lumbar spine. These changes may lead to back pain. Correction of kyphosis of the thoracolumbar spine may obviously decrease over lordosis of the lumbar spine and inclination of vertebral slip, and may further decrease the overload to the posterior column of the spine and relieve back pain. Osteotomy combined with anterior and posterior procedures is effective and safe in the correction of kyphosis of the thoracolumbar spine.

Adolescent↗
PubMed2000

[A color analysis of the Han dynasty's Yangling Tombs colored pottery figurine by spectroscopy].

Many colored pottery figurines have been discovered from Yangling Tombs in which Han Jingdi, Qi LIU, the fourth emperor of Xi Han dynasty was buried together with his Wang empress. They were of important academic and aesthetic value. The analysis of the colored pottery figurines from Yangling Tombs of Han Dynasty was realized by X-ray diffraction, emission spectrum, infrared spectrum, X-ray fluorescence and fiber optics reflectance spectroscopy(FORS). Consequent results showed that the colored components were respectively mercuric(II) sulphide(HgS), ferric(III) oxide(Fe2O3), and Carbon(C), among which mercuric(II) sulphide was an artificial pigment.

English Abstract↗
PubMed1999

[Bone tissue engineering seeded with bone marrow stromal cells].

OBJECTIVE: To assess the ability of bone graft substitutes to support the growth of cells in vitro and new bone formation in vivo. METHODS: The methods of tissue engineering were employed, the bone marrow derived stromal cells were seeded onto blocks of hydroxypatite (HA), cultured for two weeks, and implanted intermuscularly into the rabbit back muscle, scanning electron microscopy and undecalcified bone tissue sections were used to evaluate the the growth of cells in vitro and new bone formation in vivo. RESULTS: The stromal cells were attached to and grew upon the surface of the periphery HA pores, especially in the pores adjacent to the bottom of culture flasks. No cell growth was found on the surface of the central pores. At four weeks after implantation, new bone formation was observed in most HA blocks, almost all of the new bones were lamellar bone and deposited directly on the surface of the HA pore. Active osteoblast and osteoid were found on the surface of the newly formed bone, invasion of bone marrow was observed in some newly formed bone. CONCLUSION: Bone marrow stromal cells are potentially the source of seeded cells for use in bone tissue engineering, and the HA may be considered as a suitable scaffold for these cells. The findings may be useful for detailed researches on seeded cells, scaffold and implanting fashion of bone tissue engineering.

Animals↗
PubMed1999

[Construction of porous hydroxyapatite (HA) block loaded with cultured chondrocytes].

OBJECTIVE: To construct a kind of bone healing enhancing implant with cultured chondrocytes bound to hydroxyapatite (HA). METHODS: Chondrocytes were obtained from the costicartilage of rat and were cultured on the porous HA blocks, 3 mm x 3 mm x 4 mm size, for three and seven days. Scanning electron micrograph was taken to show whether the cells grew outside and inside the pore of HA block. The cells cultured on tiny glass sheet for 2 days were used to prove where the cells come from by in situ hybridization technique with alpha1 (II) cDNA probe. RESULTS: Scanning electron micrographs showed that the pores of the HA surface and inside of the blocks are filled with cultured cells, especially the longer cultured block. The cells were chondrocytes confirmed by in situ hybridization. CONCLUSION: The porous HA can be used as cell cultured substrate and chondrocyte can adhere and proliferate inside the porous HA block.

Animals↗
PubMed1999

[Motor-evoked potential in investigating neurologic function during spinal cord ischemia and reperfusion injury].

OBJECTIVE: To investigate the method monitoring the neurologic function of spinal cord ischemia and reperfusion injury. METHODS: Motor-evoked potentials (MEP)were monitored at different time points during ischemia and reperfusion of the lumbar spinal cord of the rat. RESULTS: MEP latency increased 15 minutes after ischemia (P < 0.01) and MEP amplitude decreased 25 minutes after ischemia (P < 0.01). MEP disappeared 40 minutes after ischemia and reappeared 5 minutes after reperfusion, but the latency was still longer and the amplitude was lower than the normal value (P < 0.01). The amplitude returned to normal 2 hours after reperfusion (P > 0.05) in contrast to the latency. 24 hours after reperfusion, the amplitude decreased again, and motor function of rat hind limbs was more decreased than that at early time of reperfusion (P < 0.05). CONCLUSION: MEP is a sensitive index for spinal cord ischemia and reperfusion injury.

Animals↗
PubMed1999

[An epidemiological survey and treatment of blindness in Zhangqiu city of Shandong province].

OBJECTIVE: An epidemiological survey of blindness was carried out in Zhangqiu city of Shandong province. METHODS: According to stratified random sampling rule, 11,884 persons were chosen as the sample (the sampling fraction is 1.27%) in the city. The WHO grading system for blindness was followed in the survey. RESULTS: The prevalence of blindness was found to be 0.31%, resulting chiefly from cataract (45.95%), glaucoma (24.32%) and vitreous retinal disease (13.51%). 1 016 cases of blindness caused by cataract were operated for restoration of vision, that were accounted for 73.89% of all cataract blindness estimated from the result of the survey. The rate of intraocular lens implantation in the restorative operations was 84.15% (855/1,016). After operation, the corrected vision in 64.47% of the blindness was >or= 1.0, in 21.26% between 0.6 - 0.9, in 10.24% between 0.3 - 0.5, and in 4.03% between 0.05 - 0.2. CONCLUSION: The epidemiological results show that the main cause of blindness is cataract. So it is the key objective for surgical restoration of vision in the prevention of the blindness in later days.

Adolescent↗
PubMed1998

[Human bone morphogenetic protein-2: recombinant expression in E. coli].

OBJECTIVE: To explore the way of producing human bone morphogenetic protein-2(hBMP-2) for bone healing by using the gene engeneering techniques. METHODS: hBMP-2 cDNA fragment, which consists of 3' end partial propeptide and mature peptide sequence, was inserted into the multiple cloning site of expression vector pkpL-3a via ligation. The recombinant plasmid pkpL-3a/hBMP-2 was transformed into E. coli pOp2136. By the method of restriction map, the positive expression clone was selected. SDS-PAGE analysis showed a new foreign protein band near 27,000 after induction. The yield of induced hBMP-2 accouned for 10% of the total bacterial proteins. RESULTS: The partial purified recombinant hBMP-2 was implanted into Wistar rat thigh. After 4 weeks, histological analysis showed that it induced the proliferation of mesenchymal type cells and formation of new cartilage and bone in the implantation area. CONCLUSION: The hBMP-2 produced by gene engeneering techniques has the biologic capacity of ectopic bone formation.

Animals↗
PubMed1998

[The experimental research of transforming growth factor-beta 1 expression during fracture healing].

OBJECTIVE: To observe the effect of TGF-beta 1 in the regulation of fracture healing. METHOD: The expression of transforming growth factor-beta 1 (TGF-beta 1) in different period of fracture healing was investigated by immunohistochemistry. RESULTS: It was found that the expression of TGF-beta 1 changed in different period. The cells in the cambial layer of the periostlum showed low or negative signal in the immediate injury response period. The osteoblasts differentiated from the periosteum cells stained strongly in the intramembranous ossification period, and the differentiated chondrocytes stained most strongly in the chondrogenesis period. The hypertrophic chondrocytes showed negative signal and the osteoblasts stained strongly in the endochondral ossification period. These results suggested that the expression of TGF-beta 1 was closely related to the proliferation and differentiation state of repair cells. CONCLUSION: TGF-beta 1 is intimately involved in the control of fracture healing.

Animals↗
PubMed1997

c-Myc transactivation of LDH-A: implications for tumor metabolism and growth.

Cancer cells are able to overproduce lactic acid aerobically, whereas normal cells undergo anaerobic glycolysis only when deprived of oxygen. Tumor aerobic glycolysis was recognized about seven decades ago; however, its molecular basis has remained elusive. The lactate dehydrogenase-A gene (LDH-A), whose product participates in normal anaerobic glycolysis and is frequently increased in human cancers, was identified as a c-Myc-responsive gene. Stably transfected Rat1a fibroblasts that overexpress LDH-A alone or those transformed by c-Myc overproduce lactic acid. LDH-A overexpression is required for c-Myc-mediated transformation because lowering its level through antisense LDH-A expression reduces soft agar clonogenicity of c-Myc-transformed Rat1a fibroblasts, c-Myc-transformed human lymphoblastoid cells, and Burkitt lymphoma cells. Although antisense expression of LDH-A did not affect the growth of c-Myc-transformed fibroblasts adherent to culture dishes under normoxic conditions, the growth of these adherent cells in hypoxia was reduced. These observations suggest that an increased LDH-A level is required for the growth of a transformed spheroid cell mass, which has a hypoxic internal microenvironment. Our studies have linked c-Myc to the induction of LDH-A, whose expression increases lactate production and is necessary for c-Myc-mediated transformation.

Animals↗
PubMed1997

Oncogenes in tumor metabolism, tumorigenesis, and apoptosis.

The ability of cancer cells to overproduce lactic acid aerobically was recognized by Warburg about seven decades ago, although its molecular basis has been elusive. Increases in glucose transport and hexokinase activity in cancer cells appear to account for the increased flux of glucose through the cancer cells. Herein we review current findings indicating that the c-Myc oncogenic transcription factor and hypoxia-inducible factor 1 (HIF-1) are able to bind the lactate dehydrogenase A promoter cis acting elements, which resemble the core carbohydrate response element (ChoRE), CACGTG. These and other observations suggest that the normal cell responds physiologically to changes in oxygen tension or the availability of glucose by altering glycolysis through the ChoRE, which hypothetically binds c-Myc, HIF-1, or related factors. The neoplastic cell is hypothesized to augment glycolysis by activation of ChoRE/ HIF-1 sites through direct interaction with c-Myc or through activation of HIF-1 or HIF-1-like activity. We hypothesize that oncogene products either stimulate HIF-1 and related factors or, in the case of c-Myc, directly activate hypoxia/glucose responsive elements in glycolytic enzyme genes to increase the ability of cancer cells to undergo aerobic glycolysis.

Animals↗
PubMed1997

New surgical technique for treatment of extraarticular knee ankylosis.

Laboratory and clinical studies were conducted to evaluate a treatment regimen for extraarticular ankylosis of the knee. The study evaluated the use of a porcine biomembrane to prevent quadriceps adhesions. A canine model was studied to determine the cellular response to the membrane by evaluating biopsies at 3, 7, 14, and 21 days after surgery using light and scanning electron microscopy. The results showed that there was nonspecific inflammatory cell infiltration into the base (rough) layer of the biomembrane during the first few days, although fibroblasts were the dominant cellular response 7 days later. No significant tissue ingrowth was seen on the smooth (muscular interface) surface of the membrane. The clinical study applied the information gained from the canine model to a series of 23 patients who suffered from extraarticular knee ankylosis and who were treated with a surgical procedure in which the released interface between the femur and the muscle groups was protected with a piece of porcine biomembrane. Subjects were observed from 16 to 30 months (mean, 26 months) after surgery. An average increase in knee range of motion of 86 degrees was documented, and a 100% patient satisfaction rate was noted. The technique yields satisfactory results in terms of cost, range of motion, and postoperative pain.

Adolescent↗
PubMed1997

[Foraminal and extraforaminal lumbar disc herniations].

The severity of the clinical presentations of the foraminal or extraforaminal lumbar disc herniation (FLDH or EFLDH) and its response to conservative treatment were different. In order to make clear the reasons for that and then chose the best method of treatment, two types of FLDH or EFLDH were classified in a group of 23 cases according to the location of the protruded disc shown in the films of CT or MRI. Type I: the disc protruded up to the superior pedicle closely. Type II: the disc protruded laterally mainly with slight moving up. Then two subtypes were made, subtype a: symple FLDH or EFLDH: subtype b: if combined with posterior lateral disc herniation. In total of 23 cases there were 10 of type (I a: 8, I b: 2) and 13 of type II (II a: 7, II b: 6), among of which there were 14 FLDHs and 9 EFLDHs. The clinical presentations and the results of conservative treatment were compared between the two types. The results of statistical analysis showed that the severity of damage to the nerve root and its response to conservative treatment were mainly related to the location of the protruded disc to the superior pedicle rather than the protruded disc in the foramen or extraforamen. All of cases of type I had more severe symptoms and signs, poorer results of conservative treatment and were operated on finally. However some cases of type II only had slight or even no symptoms and signs at all, 50% of the patients in the type II were cured by nonsurgical methods. So it was suggested that the cases of type I be treated surgically mainly, whereas the type II initially be treated conservatively and if failed, go to operation. The approach lateral to the pars interarticularis for the discectomy had more advantages than the other methods and could be applied in most of cases. If combined posterior lateral disc herniation was the main pathologic change in the cases of type II laminectomy with partial facetectomy might be used. The classification is reliable as it is well consisten with the findings of operations. So it is valuable for the guidance of determining the method of nonsurgical or surgical treatment.

Adult↗
PubMed1996

[Cervical intervertebral disc calcification in children: report of 10 patients].

Eleven cervical intervertebral space calcifications were studied in ten children (5 boys, 5 girls), with mean age of 9.4 years. The aetiology, symptoms, roentgenographic clinic features were analyzied. All ten patients showed evidence of calcification of the cervical intervertebral disc. One had calcification in two disc spaces of the cervical spine and associated with subluxation of C1,2. Two patients had calcification protruded into the spinal canal without symptoms of spinal cord compression. One had symptom of nerve root irritation. Eight of ten patients had symptoms which disappeared in two weeks after treatment. Eight patients had been followed over one year. The calcification disappeared from 2 to 8 months. The diagnostic criteria for the syndrome of this study are: (1) pediatric age group only; (2) local or referred pain; (3) limited cervical spine motiion; (4) evidence of inflammation; (5) visible calcification of the cervercal intervertebral disc on roentgenogram; (6) self-limited course; (7) good result after conservative treatment and good prognosis.

Adolescent↗
PubMed1996

[An experimental study on BMP gene expression in vivo].

The authors inserted the full length BMP-1 cDNA into Xbal-treated pRc/RSV plasmid via ligation, resulting in construction of pRc/RSV/BMP-1 eukaryotic expression vector. The validity of the reconstructed vector was confirmed by the restriction map. Then more reconstructed plasmids were extracted. According to the general principle of gene therapy, 100 micrograms of pRc/RSV/BMP-1 plasmid was transferred into a Balb/c mouse quadriceps by implantation under anaesthesia respectively. After 3 weeks, the BMP gene expression was detected in the mouse muscles by histoimmunochemistry.

Animals↗