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Y Fan

Publications and source records attributed to Y Fan.

At least 199 records · Page 11Linked to original sources
PubMed1994

Characterization of a novel tumor-derived cytokine. Endothelial-monocyte activating polypeptide II.

Endothelial-monocyte activating polypeptide II (EMAP II) was initially identified in the supernatant of murine methylcholanthrene A-induced fibrosarcomas (Meth A) by its capacity to activate host effector cells (Kao, J., Ryan, J., Brett, J., Chen, J., Shen, H., Fan, Y-G., Godman, G., Familletti, P., Wang, F., Pan, Y-C., Stern, D., and Clauss, M. (1992) J. Biol. Chem. 267, 20239-20247). Based on the NH2-terminal protein sequence, a full-length cDNA has been cloned which indicates that the precursor of EMAP II is a unique, leaderless, single polypeptide chain with predicted molecular mass approximately 34 kDa and that the mature form released by Meth A cells corresponds to approximately 20 kDa. Purified recombinant mature EMAP II (EMAP II, approximately 20 kDa form) activated endothelial cells with resulting elevation of cytosolic free calcium concentration, release of von Willebrand factor, induction of tissue factor, and expression of the adhesion molecules E-selectin and P-selectin. Neutrophils exposed to EMAP II demonstrated elevated cytosolic free calcium concentration, peroxidase generation, and chemotaxis. EMAP II also activated mononuclear phagocytes elevating cytosolic free calcium concentration, inducing tumor necrosis factor-alpha (TNF) and tissue factor, and stimulating chemotaxis. Systemic infusion of EMAP II into C3H/HeJ or Balb/c mice was associated with systemic toxicity, pulmonary congestion, and the appearance of TNF, interleukin-1 and -6 in the plasma. A single intra-tumor injection of EMAP II into Meth A sarcomas induced acute thrombohemorrhage and partial tumor regression. Local injection of EMAP II into a tumor resistant to the effects of TNF, murine mammary carcinoma, rendered it sensitive to subsequently administered TNF, which resulted in acute thrombohemorrhage and partial regression. These data suggest that recombinant EMAP II, a tumor-derived cytokine, has properties of a proinflammatory mediator with the capacity to prime the tumor vasculature for a locally destructive process.

Amino Acid Sequence↗
PubMed1994

Molecular cloning, tissue distribution and chromosomal localization of a novel member of the opioid receptor gene family.

A cDNA was isolated from rat brain by low stringency hybridization with the rat mu opioid receptor cDNA. Sequence analysis of this clone indicated that it contains an open reading frame capable of encoding a 367 amino acid protein. The deduced amino acid sequence of this protein shows high degrees of homology to all three opioid receptors, mu, kappa, and delta, suggesting that it is a member of the opioid receptor gene family. RNA blot analysis detected high level expression of the receptor mRNA in the brain. Southern blot analysis suggests that it is a single-copy gene, and mapping studies localized the gene on mouse chromosome 2. Despite the high sequence homologies between this protein and the other opioid receptors, expression studies of this clone in COS-7 cells did not show binding to [3H]diprenorphine, a ligand that binds to the other three opioid receptors. Furthermore, co-expression of this receptor with a G protein-activated potassium channel in Xenopus oocytes did not show functional coupling upon stimulation with mu, kappa and delta agonists. Given the similar degrees of high homology to the mu, kappa and delta opioid receptors and the lack of apparent affinity for their ligands, this receptor does not appear to belong to any of the three known classes of opioid receptors. Rather, it represents a novel member of the opioid receptor gene family, not identified from previous pharmacological studies.

Amino Acid Sequence↗
PubMed1994

Intrinsic differences in MyoD and myogenin expression between primary cultures of SJL/J and BALB/C skeletal muscle.

The time course of expression of the skeletal muscle-specific regulatory genes MyoD and myogenin was studied in primary cultures of skeletal muscle from adult SJL/J and BALB/c mice. In situ detection of expression with MyoD and myogenin riboprobes and myogenin antibody showed that the onset of expression of these genes occurred earlier in cells from SJL/J mice. Probe-positive cells and myotubes were also more frequent in cultures from SJL/J mice than in BALB/c. The onset of expression of MyoD and myogenin was delayed in cultured cells relative to the time course seen following injury in vivo. Myogenin protein was demonstrated in replicating cells and all myogenin-positive cells expressed desmin. The observed strain-specific difference infers a greater intrinsic myogenicity of cells in SJL/J muscle in vitro and reflects the superior capacity for new muscle formation previously reported in SJL/J mice in vivo.

Animals↗
PubMed1994

Carbonic anhydrase II gene transcript in cultured osteoclasts from neonatal rats: effect of calcitonin.

Carbonic anhydrase II (CA II), an enzyme catalyzing the interconversion of CO2 and water to HCO3- and protons, has a key role in osteoclastic bone resorption, but little is known of the regulation of CA II gene expression by calcitonin. Analysis of mRNA in osteoclasts has been difficult because of the problems of obtaining sufficient number of purified osteoclasts from bone. In this study, however, we have investigated the regulation of CA II mRNA in rat osteoclasts and their putative mononuclear precursors by using in situ hybridization. We have found that the CA II gene is expressed at high levels in osteoclasts and what are probably their maturing mononuclear precursors. Measurement of CA II mRNA in cultured osteoclasts and their putative mononuclear precursor cells by cytophotometry provided evidence that calcitonin, a direct inhibitor of mammalian osteoclast activity, reduces the levels of CA II mRNA in a dose dependent manner; maximum reduction was observed at a concentration of 100 pM of calcitonin. In addition, calcitonin reduced the number of CA II mRNA-positive mononuclear precursor cells. The results also suggest that expression of the CA II gene is a feature of cells committed to the osteoclast lineage.

Acid Phosphatase↗
PubMed1994

The combined use of soybean agglutinin and immunomagnetic beads for T lymphocyte subset depletion of bone marrow allografts: a laboratory analysis.

The prevention of graft-versus-host disease by T-lymphocyte depletion of allografts prior to bone marrow transplantation has resulted in an increase in graft failure/rejection and relapse of disease. Evidence for the selective roles of specific T-lymphocyte subsets in each of the engraftment, graft-versus-host disease, and disease relapse processes has been presented, but sufficient clinical verification to support any hypothesis in this regard is lacking. In this paper we describe a convenient and highly flexible clinical laboratory method for depletion of specific T-lymphocytes in controllable quantities by the use of select monoclonal antibodies. Almost 3 log10 removal of CD2+ and CD8+ cells without significant loss of hematopoietic progenitors (CFU-GM, BFU-E, and CD34+ cells) can be reproducibly achieved. This method, employing soybean agglutination and immunomagnetic beads, is potentially adaptable to depletion of any cell subset or any tumor cell for which unique cell-surface antigen characteristics have been defined. In addition, our protocol is equally suited to the positive selection of stem cells and hematopoietic progenitors bearing the CD34 surface antigen.

Bone Marrow Transplantation↗
PubMed1994

[Unstable DNA sequence and methylation in fragile X syndrome].

Fragile X syndrome is characterized as an inherited unstable DNA sequence: the increasement of (CGG)n copy number. It suffered from the inactivation of FMR-1 (fragile X mental retardation 1), which is inhibited by amplification of (CGG)n and methylation of CpG island. The (CGG)n repeat variation in normal Chinese population was detected by PCR with sequencing gel analysis. We also analysed the amplification of (CGG)n and methylation of CpG island at Xq27.3 from 15 individuals in 6 families by Southern hybridization. These results indicate that abnormal methylation of CpG island always occurs in Fra (X) patients together with large amplification of (CGG)n. The (CGG)n could be either stable or amplified in springs of carrier females. These suggest that there would be a new genetic mechanism dynamic mutation.

Base Sequence↗
PubMed1994

Gene expression of transforming growth factor-beta 1 and its type II receptor in giant cell tumors of bone. Possible involvement in osteoclast-like cell migration.

Giant cell tumor of bone (GCT) is a relatively rare skeletal neoplasm characterized by multinuclear giant cells (osteoclast-like cells) scattered in a mass of mononuclear cells. The currently favored hypothesis for the origin of cells within GCT is that the multinuclear giant cells are reactive osteoclasts, whereas the truly neoplastic cells are the major component of the mononuclear population. However, the pathological significance and the precise relationship of tumor cells and osteoclast-like cells in GCT have not been fully established. In this study, we evaluated two GCTs for the presence of transforming growth factor-beta 1 (TGF-beta 1) and TGF-beta type II receptor gene transcripts and attempted to establish a possible role for TGF-beta 1 in the interaction between tumor cells and osteoclast-like cells. By using in situ hybridization and Northern blot analysis, we have demonstrated that TGF-beta 1 mRNA transcript is consistently detected in both tumor mononuclear cells and osteoclast-like cells, whereas TGF-beta type II receptor gene transcript is only present in osteoclast-like cells. Moreover, isolated rat osteoclasts were tested for their ability to migrate in response to GCT-conditioned medium (GCTCM) in an in vitro chemotactic assay. Our results showed that GCTCM stimulates the migration of osteoclasts in a dose-dependent manner. Interestingly, only osteoclasts containing less than three nuclei can migrate through 12-mu pore filters. Addition of monoclonal antibody against TGF-beta significantly reduced but did not abolish the chemotactic activity of GCTCM. Moreover, TGF-beta type II receptor mRNA has been demonstrated in the normal rat osteoclasts and may be involved in the chemotactic action of TGF-beta 1. We concluded that TGF-beta 1, possibly in concert with other cytokines, is involved in the recruitment of osteoclast-like cells in GCT by acting in an autocrine or paracrine fashion.

Adult↗
PubMed1994

Clinical and laboratory comparison study of refrigerated and cryopreserved bone marrow for transplantation.

Refrigerated storage for short-term preservation of bone marrow is an alternative to cryopreservation where chemotherapeutic regimens include drugs with short in vivo half-lives. We performed a clinical and laboratory comparison of bone marrow stored at 4 degrees C for up to 9 days to bone marrow cryopreserved at -90 degrees C for autotransplantation. After adjusting for the confounding effects of disease type or sex, no clinically meaningful variation in post-transplant course between refrigerated storage and cryopreserved was found. Therefore, the data presented in this study suggest that the clinical recovery indices following transplantation between the two storage groups are essentially equivalent. One potential advantage to refrigerated storage, however, is that it may provide an opportunity for extended exposure to growth factors and/or purging agents in vitro prior to transplantation. To prepare for an in vitro analysis of this hypothesis, we concentrated the stem cell population and compared the nucleated cell recovery, viability and colony forming potential following refrigerated storage of whole bone marrow and buffy coat to cryopreserved bone marrow stored for the same interval. While the nucleated cell recovery for cryopreserved marrow was significantly greater than for refrigerated storage, the viability and colony forming potential of the refrigerated storage was superior or equivalent, independent of prior processing.

Adolescent↗
PubMed1993

Detection of mRNA for carbonic anhydrase II in human osteoclast-like cells by in situ hybridization.

Carbonic anhydrase II (CA II) plays an important role during osteoclastic bone resorption. Biochemical investigations of gene expression of CA II, however, have been hampered by difficulty in obtaining sufficient numbers of purified osteoclasts. In this study, we describe a nonradioactive, digoxigenin-labeled cDNA in situ hybridization technique capable of determining the pattern of CA II gene expression in human osteoclast-like cells (OC-like cells) at the single-cell level. The results showed that CA II mRNA was located in the cytoplasm of both imprinted and cultured OC-like cells from a giant cell tumor of bone. On the other hand, no evidence of CA II mRNA was found in either the mononuclear cells (tumor cells) of giant cell tumor of bone or osteosarcoma cells. There is a significant correlation between in situ hybridization and northern blot analysis for CA II mRNA in both the giant cell tumor of bone and the osteosarcoma. Our results also indicated that quantitation of in situ hybridization can be achieved by computed cytophotometry.

Adult↗
PubMed1993

Induction of changes in the secondary structure of globular proteins by a hydrophobic surface.

Circular dichroism, ellipsometry and radiolabeling techniques were employed to study the induction of changes in the secondary structure of BSA, myoglobin and cytochrome C by a hydrophobic surface. The results showed that adsorbed protein molecules lose their ordered native structure in the initial stage of adsorption and the structure appears to be a random or disordered conformation. Protein molecules adsorbed in later stages adopt a more ordered secondary structure (alpha helix and beta structure). The changes of secondary structure of globular proteins induced by a hydrophobic surface can be explained by the steric interaction between adsorbed proteins as well as by hydrophobic interactions during the adsorption process. In addition, there is obviously an intermediate stage in which the protein molecules are mainly in the beta structure, indicating that for certain proteins, the beta structure may be a more stable secondary structure than alpha helix on the hydrophobic surface.

Adsorption↗
PubMed1993

The migration and intermixing of donor and host glia on nitrocellulose polymers implanted into cortical lesion cavities in adult mice and rats.

The fate of neonatal glia (mostly glial fibrillary acidic protein-positive astrocytes), cultured on nitrocellulose papers and implanted into cortical lesion cavities, was examined in adult mice and rats. In mice, a Y-chromosome-specific probe and in situ hybridization techniques were used to identify male cells. Male-female grafts allowed visualization of donor glia and their behaviour after transplantation; female-male grafts allowed an analysis of how host cells responded to the presence of the implants. There was substantial intermixing of cells, with many donor glia migrating away from the implants and host cells migrating onto both sides of the nitrocellulose paper. In rats, donor glia were labelled with fluorescein-conjugated latex microspheres prior to transplantation on nitrocellulose polymers. The rat data were broadly consistent with those obtained from the mouse; moreover, immunohistochemical studies in rats suggested that the majority of host cells migrating onto the previously cell-coated papers were astrocytes. In a number of studies, glia-coated polymers have been used in an attempt to promote the regrowth of axons across lesion sites in the brain and spinal cord. The present work suggests that both transplanted and host glia may influence the regenerative growth seen in such implants.

Animals↗
PubMed1993

Hemodynamic and nonhemodynamic mechanism of experimental pulmonary edema in rats and the effect of anisodamine and tetramethylpyrazine--electron microscopic observation and measurement of pulmonary arterial, pulmonary arterial wedge and systemic arterial pressure (Part 2).

The pulmonary edema (PE) induced by adrenaline (AD) administration is similar to neurogenic PE. Anisodamine (ADM, 654-2, 30 mg/kg) and tetramethylpyrazine (TMP, 120 mg/kg) have shown significant preventive effects. Electron microscopic observation was carried out to study the changes of microvascular permeability, and the dynamic change of mean pulmonary arterial pressure (PAP, 40 rats), mean pulmonary arterial wedge pressure (PAWP, 20 rats) and mean carotid arterial pressure (CAP) were also measured. The results suggested that both ADM and TMP have significant inhibitory effects on PAWP and CAP increase, as well as on the damage responsible for the increase of microvascular and alveolar permeability.

Adrenergic alpha-Agonists↗
PubMed1993

Treatment of chronic allograft rejection.

Chronic renal allograft rejection at present the most important factor affecting long-term graft survival, and effective therapeutic method is still lacking. This article reports 43 cases of chronic renal rejection treated from January 1989 to April 1992. Effective result was obtained in 27 cases (62.8%). The authors believe that increasing dosage of the immunosuppressants is an effective method for the management of chronic renal rejection and the earlier the treatment is given the better the results would be. The selection and the regulation of the dosage of the immunosuppressants should be determined according to the individual situation.

Adolescent↗
PubMed1992

Survival and migration of transplanted male glia in adult female mouse brains monitored by a Y-chromosome-specific probe.

A Y-chromosome-specific probe and in situ hybridization technology have been used to monitor the survival and migration of neonatal male glia isografted to the left cerebral hemisphere of adult female mice. More than 95% of the cultured donor glia were glial fibrillary acidic protein (GFAP)-positive astrocytes. By 4 weeks, large numbers of transplanted glia were found in both cerebral hemispheres; the extent of glial migration was greatest in white matter tracts. This method provides a new way of identifying all surviving donor cells within the brains of immunologically compatible hosts.

Animals↗