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Biomedical subjects

X Du

Publications and source records attributed to X Du.

At least 163 records · Page 9Linked to original sources
PubMed1995

Superficial carcinomas of the esophagus and gastric cardia. A clinicopathological analysis of 141 cases.

From January 1970 to June 1992, 141 patients with superficial esophageal and cardiac carcinomas (SEC and SCC) underwent surgical treatment. Of the 141 patients 128(90.8%) had slight symptoms related to swallowing, and the remaining 13(9.2%) were asymptomatic. Balloon cytology and esophagoscopy proved very useful for the diagnosis of SEC and SCC, and Lugol's solution staining technique was an effective auxiliary diagnostic measure. Lymph node metastasis was not found in patients with epithelial (EP) cancer. However, it was present in one (2.9%) of 34 patients with muscularis mucosal (MM) invasion, and in 5 (8.6%) of 58 patients with submucosal (SM) cancer. The 5-year survival rates of the patients with SEC and SCC were 75.5% and 71.4%, respectively (P > 0.05). The different depth of tumor invasion including EP, MM and SM cancers showed significant differences in the 5-year survival rate (P < 0.05). Although the prognosis for the patients with lymph node metastasis is poor, we should advocate extended lymph node dissection in surgical treatment of the patients in whom MM and SM cancers are suspected.

Adenocarcinoma↗
PubMed1995

Platelet integrins.

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Amino Acid Sequence↗
PubMed1995

[Biotherapy of advanced cancer by infusion of in vitro activated autolymphocytes].

Autolymphocyte biotherapy is an adoptive cellular therapy based upon the infusion of autologous lymphocytes that have been activated in vitro by anti-CD3 monoclonal antibody and depleted of suppressor T cells by cimetidine, indomethacin and low dose of gamma irradiation. The patients also receive oral cimetidine to block suppressor T cell activity in vivo. Sixty five patients received 217 autolymphocyte infusions and toxicity was minimal with transient fever and chill accompanying 18 infusions. The efficacy of treatment in patients received more than 3 infusions were evaluated. In 37 evaluable patients, the response rate (CR+PR) was 24% (9/37). As the side reactions are mild, the treatment can be done on an outpatient basis.

Adolescent↗
PubMed1995

Placental teratoma. A case report and review of the literature.

A case of teratoma from the placenta is described. Sixteen previous reports of this entity are briefly reviewed, and the histological features, differential diagnosis and pathogenesis of the placental teratoma are discussed. Authors consider the placental teratoma a true tumor and not a fetus amorphus. Placental teratomas are extremely rare tumors. Sixteen cases have been reported since first described by Morville in 1925. Placental teratoma has not been reported in China.

Adult↗
PubMed1994

Association of a phospholipase A2 (14-3-3 protein) with the platelet glycoprotein Ib-IX complex.

Platelet adhesion to subendothelial von Willebrand factor involves receptor recognition by the platelet glycoprotein (GP) Ib-IX and initiates activation signals that contribute to primary hemostasis. We show here that GPIb-IX is specifically associated with an intracellular 29-kDa protein. The physicochemical characteristics and amino acid sequence of this protein indicate that it is identical to the human zeta-isoform 14-3-3 protein, previously characterized as a platelet phospholipase A2 (PLA2). As activation of PLA2 is an early event in GPIb-IX-mediated signaling, this result suggests that ligand occupancy of GPIb-IX may directly activate PLA2, leading to platelet activation.

14-3-3 Proteins↗
PubMed1994

Frequent loss of heterozygosity in the region including BRCA1 on chromosome 17q in squamous cell carcinomas of the esophagus.

Ninety-four esophageal squamous cell carcinomas were examined for loss of heterozygosity at several loci on the long arm of chromosome 17 (17q), using restriction fragment length polymorphism markers. Loss of heterozygosity was observed in 56 (62%) of 91 tumors that were informative with at least one marker. Comparison of these results with clinicopathological data indicated that the losses on chromosome 17q had occurred at an early stage of carcinogenesis. Detailed deletion mapping in these tumors revealed that the region commonly deleted was within the segment between loci defined by two markers at chromosomal band 17q21.3.

Alleles↗
PubMed1994

Allelotype study of esophageal carcinoma.

To investigate genetic features of esophageal cancer, we have examined 93 squamous cell carcinomas of the esophagus for loss of heterozygosity (LOH), using 41 restriction fragment length polymorphism (RFLP) markers representing all autosomal chromosomes. Allelic losses at frequencies of at least 30% were observed at loci on chromosomal arms 3p (35%), 3q (30%), 5q (36%), 9p (57%), 9q (60%), 10p (33%), 13q (43%), 17p (62%), 17q (46%), 18q (38%), 19q (32%), and 21q (37%). These results suggest that several putative tumor suppressor genes, in addition to the cyclin D and TP53 genes that are sometimes mutated in esophageal carcinomas, may be associated with development and/or progression of esophageal cancer. By a comparison of LOH on each chromosomal arm with clinicopathological parameters, we have found a significant correlation between LOH on 19q and regional lymph node metastases. Interestingly, the frequency of LOH on 17q was significantly higher in tumors in female patients (12 of 14 cases) than in those in male patients (20 of 56 cases) (P = 0.0009 by Fisher's exact test). Furthermore, we examined for mutations of the APC gene on chromosome arm 5q. Screening of nearly one third of the APC coding region, including the MCR (mutation cluster region), revealed no alterations. Therefore, although allelic loss at the APC locus is frequent in squamous cell carcinomas of the esophagus, it is likely that a gene on 5q other than APC is involved in esophageal tumorigenesis.

Alleles↗
PubMed1994

Novel expression of the tyrosine hydroxylase gene requires both acidic fibroblast growth factor and an activator.

Substances found in the soluble extract of muscle can alter the differentiative fate of certain brain neurons in culture by triggering novel expression of the gene for the catecholamine biosynthetic enzyme tyrosine hydroxylase (TH) (Iacovitti et al., 1989; Iacovitt, 1991). In this study, we demonstrate that TH induction in cultured noncatecholamine neurons from the mouse striatum requires the cooperative interaction of at least two substances found in muscle. Purification studies, combined with biological assay, revealed that one necessary component is acidic fibroblast growth factor (aFGF), and the other, an unidentified molecule(s) of < 10 kDa molecular weight that activated aFGF. Thus, muscle-derived aFGF, if incubated in the presence but not the absence of the < 10 kDa fraction of muscle, induced a dose-dependent increase in the number of striatal neurons that novelly express TH. This expression was blocked by prior incubation and protein A precipitation of the factor with polyclonal antibodies to aFGF (1:200-1:1000). Similar to muscle-purified aFGF, commercial preparations of native bovine and human recombinant aFGF (0.1-100 ng/ml) were potent inducers of TH when coincubated with the < 10 kDa activator. In contrast, basic FGF produced little and FGF-7 no induction of TH. Unlike the unidentified activating agent in muscle, heparin (20-500 mU), a known activator of aFGF, did not potentiate the factor's TH-inducing activity. Nonetheless, heparatinase (100 mU) prevented TH induction by aFGF and its activator, indicating that binding of heparan sulfated proteoglycans is necessary for the effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Long range propagation of conformational changes in integrin alpha IIb beta 3.

Integrin adhesion receptors participate in two-way transfer of information across the plasma membrane. For example, cytoplasmic events, such as activation of protein kinase C, cause an increase in the fibrinogen (Fg) binding affinity of the extracellular domain of integrin alpha IIb beta 3 ("inside-out signaling"). Conversely, ligand binding to alpha IIb beta 3 results in the generation of intracellular signals. We used anti-LIBS2, an anti-beta 3 monoclonal antibody, to understand potential mechanisms of this bidirectional signaling. Anti-LIBS2 bound to alpha IIb beta 3 with low affinity (Kd = 7.4 microM), and mimicked inside-out signaling by promoting Fg binding. The affinity of anti-LIBS2 binding was increased 20-fold (Kd = 326 nM) by addition of an Fg-mimetic synthetic peptide, RGDS. Thus, anti-LIBS2 and ligands (Fg and Fg-mimetic peptides) bind cooperatively to integrin alpha IIb beta 3, indicating a functional linkage between the ligand-binding site and the antibody-binding site. The anti-LIBS2-binding site was mapped by its binding to proteolytic and recombinant fragments of the beta 3 subunit. The epitope was located within an 89-residue region immediately adjacent to the transmembrane domain and 400 residues carboxyl-terminal to the known ligand-binding site(s). Electron microscope images of rotary shadowed ternary complexes of Fg, anti-LIBS2, and alpha IIb beta 3 revealed that the ligand-binding site and anti-LIBS2 epitope are separated by about 16 nm. This indicates that propagated long distance conformational changes can occur in alpha IIb beta 3. Such changes are likely to be involved in the bidirectional signaling function of this integral membrane protein.

Allosteric Regulation↗
PubMed1992

Inside-out integrin signalling.

Integrins are expressed by virtually all cells and play key roles in a range of cellular processes. Changes in the integrin surface repertoire provide a means of altering the strength and ligand preferences of cell adhesion. Recent research has examined the affinity modulation of integrins, a rapid and versatile mechanism of cell adhesion regulation. Studies with a prototype, alpha IIb beta 3, indicate that intracellular events influence the conformation and ligand-binding affinity of the extracellular domain of integrins. This 'inside-out' signal transduction appears to be mediated through the integrin cytoplasmic domains. In addition, in some cases affinity modulation of integrins may be cell-type specific. The clarification of the mechanisms of integrin affinity modulation should help explain rapid changes in cell adhesion that occur during cell migration, aggregation and the cell cycle.

Amino Acid Sequence↗
PubMed1992

Protective effects of berberine and phentolamine on myocardial reoxygenation damage.

The protective effects of berberine and phentolamine against anoxia and reoxygenation damage in isolated rat hearts have been investigated. Incorporation of berberine (24.5 mumol/L) in both anoxic and aerobic perfusion media resulted in a significant reduction of CPK release during the reoxygenation period, and the ultrastructural damage was reduced as compared with the control group; the myocytes in the berberine-treated group displayed mild intracellular edema, well-registered myofibrils without contracted bands, and swollen mitochondria with partially broken cristae but without dense bodies. Berberine did not inhibit calcium and sodium accumulation or magnesium and potassium loss. Treatment with phentolamine (6.6 mumol/L), an alpha-adrenoceptor antagonist, had similar effects, though the CPK release profile was shifted to the right and downwards. These results suggest that although berberine and phentolamine have some beneficial effects on myocardial reoxygenation injury, they may not abolish the injury. Therefore alpha-adrenoceptor stimulation may not be the major mechanism behind the injury.

Adrenergic alpha-Antagonists↗
PubMed1992

[A histochemical study of saikosaponins].

The root of Bupleurum chinese and B.scorzonerifolium was examined histochemically in order to clarify the distribution of saikosaponins in various tissues and parts of the root. By means of qualitative and quantitative analyses, saikosaponins, the bioactive principles in the root, were found to be abundant in the cortex outside the cambium and very little in the xylem of the root. It was also found that the thinner root hairs had the highest contents of saikosaponins, but decreased towards the thicker root head.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1992

Polymorphism of platelet glycoprotein Ib associated with variability of the 85-kDa macroglycopeptide region.

Polymorphism of platelet membrane glycoprotein Ib (GP Ib) has been described in both normal and functionally abnormal platelets. In this report we have investigated the polymorphism in one Australian Caucasian family with normal platelet function in which the following phenotypes were found: father, BC; mother, CD; son, BC; and daughter, BD; thus establishing a genetic basis for this phenomenon. The daughter's phenotype BD is highly distinctive due to the double-band pattern obtained by gel analysis. Platelets from the daughter were digested with either trypsin or elastase and the GP Ib cleavage products were examined by immunoprecipitation with anti-GP Ib-IX complex monoclonal antibodies against each of the major tryptic domains. On the basis of these studies, we have determined that the GPIb polymorphism in this family resides in the 85-kDa, macroglycopeptide region of the alpha-chain of GP Ib and not in either the 45-kDa, N-terminal region of GP Ib alpha or the membrane-associated region of the complex.

Adult↗