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G Ding

Publications and source records attributed to G Ding.

At least 19 recordsLinked to original sources
PubMed2003

Injectable bone.

Temperature-dependent polymerising polyethylene oxide hydrogel was used as a vehicle to deliver bone marrow mesenchymal cells by injection in six nude mice, four mice acting as controls, to study generation of new bone in the cell-hydrogel complex. Mesenchymal cells were harvested by in vitro cell culture, and cells were seeded into polyethylene oxide solution. The density of the suspension was adjusted to 5 x 10(7)ml(-1). The hydrogel was obtained by adjusting the temperature to over 6 degrees C. Aliquots of 0.5 ml of the cell-hydrogel complexes were injected subcutaneously into the backs of the six experimental mice, and 0.5 ml of hydrogel alone was injected into the four controls. Generation of new bone was studied by gross inspection, radiographs, and histological examination. Two months after injection hard nodes had formed subcutaneously in all six mice, whereas in the control group the hydrogel had been absorbed completely and only soft tissue was present at the site of injection. A shadow could be seen on the radiographs of all cell-seeded mice. On histological examination of the nodes there was trabecular bone and some areas of neocartilage. This method of generating new bone might be of potential clinical use.

Animals↗
PubMed2001

Dendritic cells support hematopoiesis of bone marrow cells.

BACKGROUND: We previously observed that vaccination of normal mice with bone marrow (BM) -derived dendritic cells (DCs) could increase the number of peripheral white blood cells (WBCs) and platelets. In the present study, we investigated the potential of DCs to support the hematopoiesis of BM cells in vitro and in vivo. METHODS: In the absence of exogenous cytokines, the expansion of CD34+ stem cells was observed when cultured with DC-derived supernatant or contact cocultured with DC. After culture in supernatant of DCs or contact coculture with DCs for 3 days, CD34+ progenitor cells were cultured in the semisolid media to test their ability to generate the clonogeneic cells. Then, BM cells combined with DCs or not were transferred into lethally irradiated syngeneic recipients to determine the effects of DCs on hematopoietic recovery. RESULTS: After culture in the supernatant of DCs, especially in the supernatant of OVA-DCs (OVA-stimulated DC), the proliferation of CD34+ stem cells and generation of clonogeneic cells were augmented in correspondence with the concentration of DCs. After contact coculture with DCs, the proliferation of CD34+ stem cells and generation of clonogeneic cells were more significant than that in noncontact cultures. Moreover, when cultured with DCs or supernatant of DCs, CD34+ progenitor cells were preferentially differentiated to megakaryocytes. After coculture with OVA-DCs, markedly greater generation of colony forming units-granulocyte/macrophages (CFU-GM): colony forming units-megakaryocytes (CFU-MK) was found than that in coculture with unstimulated DCs. Pretreatment of DC with antibodies to thrombopoietin (TPO), interleukin (IL) -6, IL-12, or anti-mouse intercellular adhesion molecule-1 (ICAM-1) could inhibit the ability of DCs to support the generation of CFU-GM, CFU-MK. After transplant with BM cells and DCs, the number of peripheral platelets of the recipients increased significantly and, to a lesser extent, peripheral WBC counts increased. The survival periods were significantly prolonged when the lethally irradiated mice were transplanted with BM cells combined with DCs or OVA-DCs. High levels of TPO, IL-6, and IL-12 could be detectable in the supernatant of DCs, and TPO expression by DCs was further confirmed by reverse transcription-polymerase chain reaction analysis and intracellular staining with anti-TPO antibody. CONCLUSIONS: We first demonstrated that DCs, especially antigen-stimulated DCs, can promote the expansion of hematopoietic progenitors and support hematopoiesis, preferentially support megakaryopoiesis of BM cells, by expressing soluble factors, including TPO, IL-6, IL-12, and by direct cell-to-cell interaction with stem cells in vitro and in vivo.

Animals↗
PubMed2001

Puromycin aminonucleoside induces glomerular epithelial cell apoptosis.

Glomerular epithelial cell (GEC) injury has been considered to play an important role in puromycin aminonucleoside (PAN)-induced nephrosis. We studied the effect of PAN on rat as well as human GEC apoptosis. Morphogic evaluation of GEC apoptosis and necrosis was carried out by staining with H-33342 and propidium iodide. GEC apoptosis was further confirmed by DNA fragmentation assay (by both agarose gel electrophoresis and end-labeling). To determine the dose- and time-response effect of PAN, GECs were treated with variable concentrations of PAN (10 to 500 microg/ml) for variable time periods (6 to 48 h). To determine the role of gene synthesis, we studied the effect of actinomycin D (a transcriptional inhibitor) on PAN-induced GEC apoptosis. To determine the role of free radicals, we evaluated the effect of superoxide dismutase (SOD), dimethylthiourea (DMTU), and catalase on PAN-induced GEC apoptosis. PAN induced GEC apoptosis in a dose- and time-dependent manner. PAN at a high concentration (PAN, 100 microg/ml) also induced a moderate degree of GEC necrosis. In DNA fragmentation assays PAN-treated GECs showed the classic ladder pattern. PAN-induced GEC apoptosis was partly attenuated with free radical scavengers, such as SOD, DMTU, and catalase. In addition, actinomycin D attenuated PAN-induced GEC apoptosis. PAN induces GEC apoptosis, which may be mediated through the generation of reactive oxygen species.

Animals↗
PubMed2001

Tubular cell senescence and expression of TGF-beta1 and p21(WAF1/CIP1) in tubulointerstitial fibrosis of aging rats.

Kidney aging has been recognized as a chronic process of compromised renal function and structural changes in the tubulointerstitium and glomerulus. Cell senescence is associated with alterations in cell structure and function, including expression of cytokines and structural and regulatory components of extracellular matrix proteins. In this investigation, we tested the hypothesis that senescent renal cells may accumulate in vivo with advancing age. We also evaluated the expression of transforming growth factor (TGF)-beta1 and p21WAF1/CIP1 in aging kidneys. Sprague-Dawley rats at the ages of 3, 12, and 24 months were used for this study. Renal tissues were processed for morphometric and senescence analysis. Expression of TGF-beta1 and p21WAF1/CIP1 was evaluated by Northern or Western blot analysis and immunohistochemistry. Substantial tubulointerstitial injury occurred at the age of 12 months, but significant glomerular structure alteration was observed at the age of 24 months. Tubular cells developed senescence, which was detected by beta-galactosidase staining. This staining increased in frequency and intensity with age. Renal cortices showed a significant increase in the mRNA expression for TGF-beta1 and protein level for p21WAF1/CIP1. The enhanced expression of TGF-beta1 and p21WAF1/CIP1 was localized in the tubulointersititial cells. These data suggest that tubular cells undergo senescence and express increased TGF-beta1 and p21WAF1/CIP1 with advancing age. These age-related cellular and molecular alterations may play an important role in the initiation and/or progression of tubulointerstitial fibrosis and glomerulosclerosis in aging.

Animals↗
PubMed2001

Cephalometric image analysis and measurement for orthognathic surgery.

Automatic identification of landmarks in cephalometry is very important and useful for orthognathic surgery. A computerised automatic cephalometric analysis system (CACAS), based on image processing, is presented. For an original X-ray image, median filtering and histogram equalisation are used to improve image quality. The edge of an X-ray image is detected by a wavelet transform and Canny filter. Seventeen landmarks in cephalometry are successfully identified by knowledge-based edge tracing and changeable templates. Seventy-three measurements based on distances, angles and ratios between landmarks are computed automatically. The reliability of the landmarks and the validity of the measurements are compared for automatic and manual operation. The values of measurements obtained by CACAS are more precise and reliable: the mean error for linear measurements is less than 0.9mm; the mean error for angular measurements is less than 1.2 degrees. The rate of validity is over 80%, even if the image quality is poor. For an image with a high signal-to-noise ratio, the rate of validity of landmarking and measurements using the CACAS system is over 90%.

Cephalometry↗
PubMed2001

Optimization of view ordering for motion artifact suppression.

Motion artifacts in MRI may be reduced by optimized view ordering. Extensive simulations of view-ordering techniques were performed on high-resolution phantom images to determine the best strategy for distributing motion in k-space. Although not exhaustive, simulation results indicate that minimizing motion at the center of k-space is critical to overall image quality. For 2D imaging, using edge-center-edge view order and setting the readout direction parallel to the direction of the motion produces the sharpest point spread function and the lowest image energy error. For 3D imaging, using an edge-center-edge view order proves to be the optimum choice in general. Given these observations, several important issues regarding the measurement of motion effects are discussed.

Algorithms↗
PubMed2001

An epidemiological survey on neonatal jaundice in China.

OBJECTIVE: To provide epidemiological data for revising the diagnostic criteria of neonatal hyperbilirubinemia in China. METHODS: A survey was performed among full-term infants in multiple centers throughout the country. From less than 24 hours after birth, the infants' bilirubin levels were measured every day until the peak level fell to less than 68.4 mumol/L. Auditory brainstem responses were assessed in 56 infants randomly chosen from those with serum bilirubin levels of higher than 220.5 mumol/L. RESULTS: Jaundice in most infants was detected at 2-3 days after birth. The bilirubin level usually reached a peak level of 204 +/- 54.69 mumol/L at 5 days after birth and then fell. Among the 875 infants, the serum bilirubin levels in 34.4% of neonates were higher than 220.5 mumol/L. The mean serum bilirubin level of the infants during the first week after birth varied with geography (P < 0.001) and season (P < 0.001). The serum bilirubin level was significantly associated with gestation age (P < 0.01), delivery method (P < 0.01), weight loss (P < 0.001), and PCV elevation (P < 0.001) during the first three days after birth. CONCLUSIONS: The start time of neonatal jaundice was similar to that reported elsewhere, but the mean peak level in our study was higher than the reported. It is suggested that the diagnostic criteria for neonatal hyperbilirubinemia in China should be strict.

Bilirubin↗
PubMed2001

[Analysis of tannins in Fructus Chebulae and its confusion varieties by HPCE].

AIM: To analyze the hydrolyzable tannins-chebulinic acid (I) and chebulagic acid(II) in Fructus Chebulae and its confusion varieties by using high performance capillary electrophoresis (HPCE) method. METHODS: Using a capillary (375 microns OD x 50 microns ID; 81.5 cm x 61.5 cm) and a power supply set at 24 kV, with phosphate-borate buffer containing 20 mmol.L-1 Na2HPO4-60 mmol.L-1 boric acid and a UV detector at 280 nm, sample solution was loaded in decompression mode at the positive end of the capillary, the loading time was 5 s. RESULTS: The linear ranges of I and II were 0.0842-0.842 and 0.842 and 0.0940-0.940 mg.mL-1 respectively, the correlation coefficient were 0.9966 and 0.9957, the average recoveries were 95.6% (RSD = 4.0%, n = 5) and 95.0% (RSD = 4.4%, n = 5), the RSDs (n = 5) of measurement precision test were 2.2% and 1.7%, the RSDs (n = 6) of reproduction test were 5.4% and 4.0% respectively. The contents of I and II were obviously interrelated with the variety and characteristics of Fructus Chebulae, the contents of I and II in the confusion varieties of Fructus Chebulae were very low. CONCLUSION: It is suitable to use I and II as the criterion in quality evaluation of Fructus Chebulae, and the HPCE method is effective for quality evaluation of the crude Fructus Chebulae.

Benzopyrans↗
PubMed2001

[Measurement of waveguide depth in proton-exchanged LiNbO3 by infrared absorption spectroscopy].

A novel method for determining proton-exchanged LiNbO3 waveguide depth by infrared absorption spectroscopy was proposed. The method overcomes the shortcoming that the conventional prism-coupling + IWKB technique is only applicable to the multimode waveguides. For the commonly used single-mode waveguides, however, it is helpless. The experimental results indicated that this method has good accuracy.

Absorptiometry, Photon↗
PubMed2000

Suppression of heat-induced HSP-70 by simultaneous exposure to 50 mT magnetic field.

Effect of extremely low frequency magnetic field (ELFMF) at 50 mT and 60 Hz on heat-induced expression of heat shock protein 70 (hsp-70) was examined in HL60RG cells. No increase in hsp-70 production was observed in the cells after exposure to 50 mT ELFMF alone. Simultaneous exposure to 50 mT ELFMF in combination with mild heat at 42 and 40 degrees C suppressed heat-induced hsp-70 expression. The suppression of hsp-70 occurred when cells were simultaneously exposed to both for longer periods of more than 5 h. However, the suppression of hsp-70 was not observed at a magnetic density of 5 and 0.5 mT. This result suggests that exposure to 50 mT ELFMF may act on a protection against the concomitant mild heat stress in HL60RG cells.

Blotting, Western↗
PubMed2000

Breath-hold three-dimensional contrast-enhanced coronary MR angiography: motion-matched k-space sampling for reducing cardiac motion effects.

A view order that matches k-space sampling to cardiac motion within the acquisition window was developed for breath-hold three-dimensional contrast material-enhanced coronary magnetic resonance angiography. In vivo experiments in seven volunteers demonstrated that blurring was substantially reduced with this motion-matched view order as compared with the standard centric view order. Coronary arteries were well delineated.

Adult↗
PubMed2000

Conditioned immunosuppressive effect of cyclophosphamide on delayed-type hypersensitivity response and a preliminary analysis of its mechanism.

In the present study, camphor odor and intraperitoneal (i.p.) injection of cyclophosphamide (CY) were used as conditioned stimulus (CS) and unconditioned stimulus (US), respectively. In the unconditioned group, mice were exposed to camphor odor for 1 h followed by an i.p. injection of CY (75 mg/kg). On the next day, the above CS/US association trial session was repeated followed by smearing dinitrochlorobenzene (DNCB) on mouse abdominal skin for sensitizing the animal for delayed-type hypersensitivity (DTH) response. Five days after DNCB sensitization, mice were exposed to camphor odor (1 h), followed by an i.p. injection of CY, and then DNCB was smeared on the left ear of mice for the challenge of DTH response. Both the left/right ear weight ratio and the activity of leukocyte migration inhibitory factor (LMIF) were used as the index of DTH response, which was done 24 h after DNCB challenge. In the conditioned group, the treatment was the same as that in the unconditioned group, except that normal saline was injected on day 5 instead of CY. Furthermore, in order to analyze the mechanism of the conditioned response (CR), the mouse serum from the conditioned group (CR serum) was injected into normal mice 6 h prior to DNCB challenge. Results showed that in the conditioned group, left/right ear weight ratio and LMIF activity were statistically lower than that in the DTH group, and there was no difference between conditioned and unconditioned groups. Thus, an animal model of conditioned immunosuppressive response had been established. The results also showed that after CR serum was injected into normal mice, DTH response was also significantly suppressed. However, if CR serum was treated with dialysis (10,000 molecular weight cut-off), the suppressive effect of CR serum on DTH response disappeared. Taken together, the data suggested that a chemical compound(s) in serum, with a molecular weight less than 10,000, was important in mediating the conditioned immunosuppressive response. This may be a very important molecule(s) that could be very critical to our understanding of the interaction between the central nervous system and immune function.

Animals↗
PubMed2000

Transforming growth factor beta induces mesangial cell apoptosis through NO- and p53-dependent and -independent pathways.

BACKGROUND: Because transforming growth factor beta (TGF-beta) has been shown to have a bimodal effect on mesangial cell (MC) proliferation, we studied its effect on MC apoptosis. METHODS: Cultured mouse MCs were used to evaluate the effect of TGF-beta. Morphologic evaluation of MC apoptosis was performed by staining cells with H-33342 and propidium iodide. To confirm the effect of TGF-beta on MC apoptosis, DNA was extracted from control and TGF-beta-treated MCs and run on gel electrophoresis. We evaluated the effect of NG-nitro-L-arginine methyl ester (L-NAME), a nitric oxide (NO) synthase inhibitor, on TGF-beta-induced MC apoptosis to determine the role of NO and studied the effect of sodium nitroprusside (SNP) and SNAP (S-nitroso-N-acetyl-penicillamine) on MC apoptosis to confirm the effect of NO. We examined the role of p53 by studying the effect of TGF-beta on MCs derived from p53 knockout mice (p53KO-MC) as well as a normogenic strain (N-MC). We also examined the effect of TGF-beta, SNP, and SNAP on apoptosis of p53 mutant (MDAMB-231) and wild-type p53 (MCF-7) breast cancer cell lines. In addition, Western blots were generated from control, TGF-beta-treated, and SNAP-treated MCs and probed for the expression of p53. RESULTS: TGF-beta promoted MC apoptosis. Moreover, TGF-beta-treated MCs displayed integer multiples of 180 base pairs (ladder pattern). L-NAME inhibited TGF-beta-induced MC apoptosis. Furthermore, SNP and SNAP, NO donors, promoted MC apoptosis. TGF-beta also enhanced the MC expression of p53. TGF-beta induced only a moderate degree of apoptosis in MCs derived from p53KO-MC when compared with N-MCs. Similarly, the TGF-beta-induced apoptosis of MDAMB-231 was of a moderate degree when compared with MCF-7 cells. CONCLUSIONS: We hypothesize that TGF-beta promotes MC apoptosis through NO generation and p53-dependent and -independent pathways.

Animals↗
PubMed2000

Calcitonin gene-related peptide in Langerhans cells in psoriatic plaque lesions.

OBJECTIVE: To study the mechanism of stress exacerbating psoriasis and the involvement effect of neuropeptides in psoriatic pathogenesis, we investigated the expression and secretion of calcitonin gene-related peptide (CGRP) in psoriatic lesions, then identified the target cells of CGRP, the characters of CGRP positive dendrite cells and the source of CGRP in psoriatic plaque lesions. METHODS: Specific radioimmunoassay (RIA) and immunohistochemistry staining methods were used to determine CGRP secretive content and the target cells of CGRP in psoriatic plaque lesion tissue of vulgaris psoriasis. Double immunofluorenscence staining was done on psoriatic plaque lesion sections by first using rabbit anti-human CGRP antibody and mouse anti-human CD1a antibody, second using PE-conjugated anti-mouse immunoglobulin and FITC-conjugated anti-rabbit immunoglobulin. Confocal laser microscope showed the psoriatic lesion sections. Then both digoxigenin labelled anti-sense and sense RNA probe of CGRP were synthesized to make sure the source of CGRP on the dendrite cells. The psoriatic lesion sections were studied by in situ hybridization. RESULTS: The content of CGRP in vulgaris psoriatic plaque lesions was higher than that of normal controls (P < 0.01). CGRP was also found on the dermal microvascular endothelial cells and the epidermal dendrite cells in psoriatic plague lesions. Further study showed that CGRP existed on the surface of epidermal CD1a + Langerhans cell in psoriatic plaque lesion. The CGRP mRNA expressed around the nucleus of the Langerhans cells in psoriatic lesion. CONCLUSIONS: The pathogenesis of psoriatic plaque lesions was closely related to the overexpression of neuropeptide CGRP. The CGRP contacted with the dermal microvascular endothelial cells and epidermal dendrite cells in psoriatic plaque lesion. The CGRP positive epidermal dendrite cell was CD1a + Langerhans cell. The Langerhans cell itself expressed CGRP mRNA.

Adult↗
PubMed2000

[Assay of three hydrolyzable tannins in Fructus Chebulae from different habitats by RP-HPLC].

Three hydrolyzable tannins chebulinic acid (I), chebulagic acid(II) and 1,3, 6-tri-O-galloyl-beta-D-glucose (III) in Fructus Chebulae from different habitats were determined by RP-HPLC method. The contents of I and II were obviously interrelated with the variety and characteristics of Fructus Chebulae. It's suitable to use I and II as indexes in quality evaluation of the crude drug of Fructus Chebulae.

Benzopyrans↗
PubMed1999

Ethanol-induced macrophage apoptosis: the role of TGF-beta.

Both clinical and laboratory reports indicate that ethanol addicts are prone to recurrent infections. We hypothesize that ethanol promotes macrophage apoptosis, thus compromising the efficiency of the mononuclear phagocyte system in dealing with infection. We studied the effect of ethanol on macrophage apoptosis. Human monocytes isolated from healthy subjects after an alcohol drinking binge showed enhanced apoptosis (before, 1.2 +/- 0.3% vs after, 28.4 +/- 3.7% apoptotic cells/field). Peritoneal macrophages harvested from ethanol-treated rats also showed increased (p < 0.0001) apoptosis. DNA isolated from peritoneal macrophages of ethanol-treated rats displayed integer multiples of 200 base pairs (ladder pattern). Furthermore, macrophages harvested from ethanol-treated rats had an enhanced expression as well as accumulation of TGF-beta. In in vitro studies, ethanol promoted apoptosis of human monocytes as well as rat peritoneal macrophages. In addition, ethanol enhanced apoptosis of murine macrophages (J774) in a time-dependent manner. The ethanol-induced apoptosis was amplified by LPS and partly attenuated (p < 0.001) by anti-TGF-beta Ab. TGF-beta also promoted macrophage apoptosis in a dose-dependent manner. Moreover, ethanol enhanced TGF-beta protein production by macrophages. These results indicate that ethanol promotes macrophage apoptosis. This effect of ethanol seems to be partly mediated through the generation of TGF-beta by macrophages.

Animals↗
PubMed1999

HIV-1 gp120 envelope protein modulates proliferation of human glomerular epithelial cells.

Glomerular epithelial cells (GEC) have been demonstrated to undergo morphological alterations in human immunodeficiency virus (HIV)-associated focal glomerulosclerosis. In the present study, we evaluated the effect of HIV-1 gp120 envelope protein on the growth of cultured human (H) GEC. gp120 protein enhanced (P < 0.001) the proliferation of HGEC at lower concentrations. The mitogenic effect of gp120 protein on HGEC was further confirmed by enhanced accumulation of proliferating nuclear cell antigen (PCNA) by gp120 protein-treated cells, as compared with control cells. On the contrary, gp120 protein at higher concentrations suppressed (P < 0. 001) the growth of HGEC. To evaluate the mechanism of gp120 protein-induced HGEC growth suppression, we examined the effect of gp120 protein on HGEC apoptosis. gp120 protein at higher concentrations promoted the apoptosis of HGEC. At higher concentrations, gp120 protein also enhanced DNA fragmentation of HGEC. Anti-gp120 antibody attenuated the proliferative as well as the apoptotic effects of gp120 protein on HGEC. Because protein kinase C as well as tyrosine kinase inhibitors partially inhibited gp120-induced proliferation, gp120 appears to be activating both the protein kinase C and tyrosine kinase pathways. In addition, gp120 protein at lower concentrations enhanced mRNA expression of c-fos and at higher concentrations promoted mRNA expression of c-jun. We conclude that gp120 has a bimodal effect on proliferation of HGEC. This effect may be mediated through the activation of early growth genes.

Apoptosis↗