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Biomedical subjects

Zhen Wang

Publications and source records attributed to Zhen Wang.

At least 109 records · Page 6Linked to original sources
PubMed2003

[Clinical application of universal spine system in reconstruction of lumbar sacrum joint after resection of sacrum tumor].

OBJECTIVE: To investigate the operative indications and techniques of the universal spine system (USS) in reconstruction of the stability of the lumbar-sacrum joint after resection of sacrum tumor. METHODS: Nine patients were treated with USS after resection of sacrum tumor. Among them, there were 6 males and 3 females, aged from 34-60 years. The operation could be divided into four main procedures: 1. to resect sacrum tumor; 2. to insert the pedicle screw into the normal pedicle (L3 or L4 or L5) above the region of laminectomy; 3. to insert the lower screw into the iliac plate; 4. to put the rods, bone graft and links. RESULTS: There was no recurrence of sacrum tumor by MRI examination during 7-17 month follow-up. The pains of the lumbar-sacrum joint and the spinal nerve root were relieved obviously. The patients could stand and walked normally. There was no loose screw and no fracture of the screw and the rod. There was no appearance of the enlarged screw passage, the lessened pelvis and lowed L5 spine. CONCLUSION: Reconstruction of the lumbar-sacrum joint by the USS after resection of sacrum tumor is a practical operation clinically. It is characterized by the easy manipulation, few complication and stable fixation.

Adult↗
PubMed2003

[Massive frozen allografts for skeletal reconstruction: styles and affecting factors of bone union].

OBJECTIVE: To investigate the styles and affecting factors of bone union after massive frozen allografting for skeletal reconstruction owing to excision of bone tumor. METHODS: From 1992 to 1999, 85 patients suffering from bone malignant tumor were given the excision of large bone segment and treated with allografting in different methods of operation: large bone allografts with condylar articular surface in 16 cases, osteoarticular allografts in 57 cases, bone allografts in combination with prosthetic replacement of hip in 9 cases, and prosthetic replacement of knee in 3 cases. The average follow-up was 2 years and 9 months. The union time and styles of host-donor junction were determined by X-ray characters, and the results of operations were assessed according to Enneking's functional evaluation system of reconstructive procedures after surgical treatment of tumors for the musculoskeletal system. RESULTS: There were 4 kinds of basic bone union styles by the X-ray characters, there were no significant difference in the time span of bone union after fixation with different methods. Of the 85 fresh-frozen allografting procedures, more than 80% of the patients were treated with interlocked intramedullary nail and allograft-prosthesis combination, and the overall result was excellent and good. Sufficient blood supply was important for host-donor junction healing, but the function of immune response was uncertain. CONCLUSION: There were different styles of bone union after massive allografting. The recommended operative methods for massive allografts are stable internal fixation, sufficient blood supply, soft tissue repair and periosteal flap coverage.

Adolescent↗
PubMed2003

[Analysis on diagnosis, treatment and influential factors in fever patients during epidemic of severe acute respiratory syndrome].

OBJECTIVE: To analyze the etiology, therapy and influential factors in fever patients during the epidemic of severe acute respiratory syndrome (SARS), so as to define early and differential diagnosis for SARS from other disease with fever. METHODS: The epidemiological and the clinical data of 4060 patients with fever admitted to the emergency department of the Third Hospital affiliated to Peking University from March 5th to May 10th in 2003 were analyzed, and their influential factors were evaluated. RESULTS: Of 4060 patients with fever 275 cases were admitted to the isolated ward, 145 cases were diagnosed as SARS (3.75 percent), 29 belonged to suspected cases, and in 101 cases SARS was ruled out. Ninety-three cases were non-SARS-pneumonia, 2 were epidemic encephalitis, 8 were epidemic cerebrospinal meningitis, and 3 cases were epidemic hemorrhagic fever. CONCLUSION: During epidemic of SARS, the etiology of fever is influenza or other virus infection in 90 percent of patients. Non-SARS-pneumonia and infectious diseases with fever accounted for certain proportion of patients with fever. Our diagnostic level should be improved. SARS could not be ruled out only by a high white blood cells count. Chest X-ray examination have to be repeated, because abnormal chest X-ray do not always appear at the same time with fever.

Adolescent↗
PubMed2003

Effects of aging and advanced glycation on gene expression in cerebrum and spleen of mice.

OBJECTIVE: To analyze the effects of aging or advanced glycation on gene expression in the cerebrum and spleen of female C57BL/6J mice. METHODS: The gene expression profile was determined by using cDNA expression arrays containing 588 cDNA. RESULTS: Aging and advanced glycation resulted in differential gene expression patterns of cerebrum and spleen compared with young mice. Among the 80 genes detected in cerebrum, 43 exhibited a change in mRNA ratios with aging or treatment. Thirty-four changes (79%) were common in aged and D-galactose treated mice, whereas the cerebrum from aged and AGE-lysine treated mice showed common changes in expression of 38 genes (88%). Of the 86 genes detected in spleen, 29 (34%) displayed an age-related decrease in expression, whereas 3 (3%) displayed an increase in expression levels with aging. Eighteen genes from the detectable genes exhibited expression changes in both cerebrum and spleen of mice. CONCLUSIONS: The gene expression profiles of D-galactose and AGE-lysine treated mice resemble those of aged mice. Use of cDNA hybridization arrays may provide a promising tool to explore the mechanism of aging at a molecular level.

Aging↗
PubMed2002

Molecular affinity and permeability of different molecular weight chitosan membranes.

Membranes were prepared from chitosan with different molecular weights by a casting method. The molecular affinity and permeability of the membranes for sodium chloride, glucose, tyrosine, and bovine serum protein were measured at 4 degrees C and pH 7. The molecular permeability of the chitosan membranes was inversely related to molecular weight. All prepared membranes showed a molecular affinity to bovine serum protein. The higher the molecular weight of chitosan membrane, the higher the affinity and the lower permeability of the membrane to bovine serum protein.

Blood Proteins↗
PubMed2002

Quantitative study of macroscopic quantum tunneling in a dc SQUID: a system with two degrees of freedom.

To test whether the theory of macroscopic quantum tunneling (MQT) is applicable to systems with 2 degrees of freedom, we experimentally investigated the switching current distribution of a dc SQUID. Using sample parameters determined from measurements at T=4.2 K, we are able to make quantitative comparison to the theories from 8 mK to 4.2 K. The excellent agreement between the data and the MQT theory demonstrates that tunneling from the zero-voltage state of the dc SQUID is well described by the quantum mechanics.

Journal Article↗
PubMed2002

Regulation of GRIP1 and CBP Coactivator activity by Rho GDI modulates estrogen receptor transcriptional enhancement.

Estrogen receptor alpha (ER) coordinates gene expression with cellular physiology in part by controlling receptor- cofactor interactions in response to extracellular signals. We have previously shown that the Rho signaling pathway modulates ER transcriptional activation. We now demonstrate that Rho GDI-dependent increase in ER transactivation is dependent on the ER AF-2 coactivator binding site, prompting us to examine regulation of receptor coactivators by Rho GDI. Indeed, Rho GDI cooperates with GRIP1 to increase ER ligand-independent and ligand-dependent transactivation and also enhances GRIP1 transcriptional activity when GRIP1 is tethered to DNA. The GRIP1 activation domain 1 (AD1), which binds CBP/p300, is necessary for Rho GDI to modulate GRIP1 activity. Using E1A to inhibit the endogenous CBP/p300 and a Gal4-CBP fusion protein to assay CBP activity, we find that the effect of Rho GDI on ER transactivation is CBP/p300-dependent. Importantly, the ability of CBP/p300 to transduce the Rho GDI signal to ER occurs through both GRIP1-dependent and -independent pathways. These data suggest a complex interplay between ER transcriptional activation and the Rho signaling pathways through modulation of receptor cofactors, which may have evolved to coordinate receptor-dependent gene expression with Rho-regulated events, such as cell migration. We speculate that dysregulation of the Rho-ER axis may participate in cancer progression.

Animals↗
PubMed2002

Deciphering the phosphorylation "code" of the glucocorticoid receptor in vivo.

The glucocorticoid receptor (GR) is phosphorylated at multiple serine residues in a hormone-dependent manner, yet progress on elucidating the function of GR phosphorylation has been hindered by the lack of a simple assay to detect receptor phosphorylation in vivo. We have produced antibodies that specifically recognize phosphorylation sites within human GR at Ser(203) and Ser(211). In the absence of hormone, the level of GR phosphorylation at Ser(211) was low compared with phosphorylation at Ser(203). Phosphorylation of both residues increased upon treatment with the GR agonist dexamethasone. Using a battery of agonists and antagonists, we found that the transcriptional activity of GR correlated with the amount of phosphorylation at Ser(211), suggesting that Ser(211) phosphorylation is a biomarker for activated GR in vivo. Mechanistically, the kinetics of Ser(203) and Ser(211) phosphorylation in response to hormone differed, with Ser(211) displaying a more robust and sustained phosphorylation relative to Ser(203). Analysis of GR immunoprecipitates with phospho-GR-specific antibodies indicated that the receptor was phosphorylated heterogeneously at Ser(203) in the absence of hormone, whereas in the presence of hormone, a subpopulation of receptors was phosphorylated at both Ser(203) and Ser(211). Interestingly, biochemical fractionation studies following hormone treatment indicated that the Ser(203)-phosphorylated form of the receptor was predominantly cytoplasmic, whereas Ser(211)-phosphorylated GR was found in the nucleus. Likewise, by immunofluorescence, Ser(203)-phosphorylated GR was located in the cytoplasm and perinuclear regions of the cell, but not in the nucleoplasm, whereas strong phospho-Ser(211) staining was evident in the nucleoplasm of hormone-treated cells. Our results suggest that differentially phosphorylated receptor species are located in unique subcellular compartments, likely modulating distinct aspects of receptor function.

Amino Acid Sequence↗
PubMed2002

Coherent temporal oscillations of macroscopic quantum states in a Josephson junction.

We report the generation and observation of coherent temporal oscillations between the macroscopic quantum states of a Josephson tunnel junction by applying microwaves with frequencies close to the level separation. Coherent temporal oscillations of excited state populations were observed by monitoring the junction's tunneling probability as a function of time. From the data, the lower limit of phase decoherence time was estimated to be about 5 microseconds.

Journal Article↗
PubMed2002

Substituted N-(3,5-dichlorobenzenesulfonyl)-L-prolyl-phenylalanine analogues as potent VLA-4 antagonists.

A series of substituted N-(3,5-dichlorobenzenesulfonyl)-L-prolyl- and alpha-methyl-L-prolyl-phenylalanine derivatives was prepared as VLA-4/VCAM antagonists. The compounds showed excellent potency with a wide variety of neutral, polar, electron withdrawing or donating groups on the phenylalanine ring (IC50 approximately 1 nM). Heteroaryl ring substitution for phenylalanine was also well tolerated. Pharmacokinetic studies in rat were performed on a representative set of compounds in both series.

Animals↗
PubMed2002

Study of the effects of LPS on the TACE gene expression and its function.

In order to investigate the effects of LPS on the TACE gene transcription and expression and its regulating effect on the TM-TNF secretion, in vitro studies were carried out on HL-60 cells stimulated by LPS. TACE, TNF-alpha mRNA levels were detected by Dot-Elisa and the distribution of membrane molecules determined by flow cytometry assay and indirect immunofluorescence. The results showed that: (1) TACE was detected in or on HL-60 cells and it is predominantly localized on cell surface and to a perinuclear compartment. (2) LPS induced a time dependent increasement of TNF-alpha mRNA and enhanced TNF conversion with decreasing distribution of TNF in cell surface and increasing secretion of TNF protein. Such conversion could be inhibited by TACE ODN. (3) LPS also induced time-dependently increased expression of TACE gene and activation of its function. On the other hand, TACE protein in cell lysate and on cell surface was decreased. It was suggested that TACE molecular structure might change following its mediating membrane-anchored molecular secretion.

ADAM Proteins↗
PubMed2002

The effect of carboxymethyl-chitosan on proliferation and collagen secretion of normal and keloid skin fibroblasts.

In this study, different molecular weight CM-chitosans were prepared and the effects on the growth and collagen secretion of normal skin fibroblasts and keloid fibroblasts were investigated in vitro. CM-chitosan promoted the proliferation of the normal skin fibroblast significantly but inhibited the proliferation of keloid fibroblast. The higher CM-chitosan concentration had a higher initial effect and the lower CM-chitosan concentration had a longer affecting time to the normal skin fibroblast. The lower molecular weight CM-chitosan had significant twofold activities. The CM-chitosan could reduce the ratio of type I/III collagen in keloid fibroblast by inhibiting the secretion of collagen type I; and had no effect on the secretion of types I and III collagen in the normal skin fibroblast.

Adult↗
PubMed2002

[Comparison of long bone repair in tibia by vascularized fibular grafting of different sides].

OBJECTIVE: To evaluate the clinical effect of repair of massive bone defect in tibia by vascularized fibula grafting of either sides. METHODS: Twenty-four cases of massive bone defect in tibia, among which 14 case were repaired by vascularized fibula grafting of the other side and another 10 cases were repaired by those of the same side, from 1987 to 1997 were followed up for 3 to 13 years; the functions of the operated limbs were evaluated according to Enneking Score System, and the outcome of the fibula grafts were assessed by radiographic examination with reference to the standard established by International Symposium on Limb Salvage. RESULTS: The average recover rate of the operated limbs in those repaired by the other side grafting was 80.7%, and the average healing period of the fibula graft was 14 weeks with fracture of the graft in one case which made the operated lower limb shorten for about 2.5 cm; the fibula grafts were observed thickened in 43 weeks, on average, and the patients could walk independently without a crutch. While in those repaired by the same side grafting, the average recover rate of the operated limbs was 68.3%, the average healing period of the fibula graft was 17 weeks with fracture of the graft in 3 cases, in 2 of which the lower limbs were shortened for 2 cm and 4 cm respectively, and in the third one infection occurred and amputation was performed finally; the fibula grafts were observed thickened in 49 weeks, on average, which made it available for the patients to walk without a crutch. All of the data showed that there was a significant difference statistically between the differently treated cases. CONCLUSION: It's a good choice to repair massive bone defect in tibia by vascularized fibula grafting, and the vascularized fibula graft from the other side could promote the bone healing and accelerate the recover of the function of the operated lower limb.

Adolescent↗
PubMed2002

[Effects of conditioned medium derived from different keratinocytes on proliferation and collagen synthesis of hypertrophic scar fibroblasts].

OBJECTIVE: To observe the effects of supernatants of normal skin keratinocytes(NK) and scar keratinocytes(SK) on proliferation and collagen synthesis of hypertrophic scar fibroblasts(HSFB). METHODS: The supernatant, collected from cultured NK and SK, was added to the cultivated HSFB. The MTT-method, 3H-proline incorporation and radioimmunoassay were employed to measure the cell proliferation, collagen synthesis and secretion. RESULTS: NK supernatant could inhibit HSFB proliferation and increase the collagen synthesis, but inhibit collagen secretion, as compared with the control group. On the contrary, SK supernatant could increase collagen synthesis and secretion, which had little effects on HSFB proliferation. CONCLUSION: Keratinocytes derived from normal skin and hypertrophic scar show different effects on hypertrophic scar fibroblasts.

Cell Division↗
PubMed2002

Activation of astrocytes by advanced glycation end products: cytokines induction and nitric oxide release.

AIM: To investigate whether two kinds of in vitro prepared advanced glycation end products (AGE), Glu-BSA and Gal-BSA, could induce proinflammatory mediators IL-1beta and TNF-alpha, as well as oxidative stress and nitric oxide (NO), in astrocytes, thus contributing to brain injury. METHODS: Radioimmunoassay and RT-PCR technique were used to detect two cytokines' level and existence of receptor for AGE (RAGE). DTNB reaction was used to measure reduced glutathione (GSH) level. NO content was assayed using Griess reagent provided by Promega. RESULTS: Enhanced protein levels of both cytokines in supernatants and cell lysates of astroglia cultures were detected after treated with AGE-BSA 1 g/L, especially Gal-BSA, for 72 h. The increases were also in a concentration-dependent manner. Changes in protein levels might be attributed to changes in transcriptional levels documented by semi-quantitative RT-PCR. Both AGE-BSA could also reduce astrocytic GSH and induce NO release. RAGE was detected in astrocytes. CONCLUSION: Enhanced levels of astrocytic proinflammatory mediators IL-1beta and TNF-alpha, and oxidative stress caused by AGE might contribute to, at least partially, the detrimental effects of AGE in neuronal disorders and aging brain.

Animals↗