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Biomedical subjects

C Yang

Publications and source records attributed to C Yang.

At least 415 records · Page 23Linked to original sources

Extracorporeal circulation for great vessels surgery: a review of 131 cases.

A retrospective analysis of 131 cases of major vascular surgery, mainly aneurysms of the ascending and descending aorta, was undertaken to determine whether use of different bypass methods chosen according to location of the individual lesions resulted in improved results. For the 93 cases of ascending aortic aneurysm, the method for cardiac protection was improved by the use of continuous retrograde coronary sinus perfusion with cardioplegic blood. In sixteen cases with dissection involving the aortic arch, deep hypothermic circulatory arrest and continuous retrograde cerebral perfusion through the superior vena cava was employed for brain protection. The safe brain circulation arrest time was thus prolonged to the longest record of 81 minutes. Among the group of 93 cases, there were four operative and four hospital deaths, giving a mortality rate of 8.6% (8/93). For the 34 cases of descending aortic aneurysms, left heart bypass was employed to avoid ischemia of the heart, lungs, brain, and the abdominal organs; the operative mortality rate was 8.8% (3/34). In three cases of interrupted aortic arch, separate upper and lower body perfusion under deep hypothermia with low flow rate perfusion for the upper body provided the necessary conditions for radical surgery. In one patient with Budd-Chiari syndrome, a total corrective surgery was achieved under right heart bypass.

Adult↗

Effect of IL-7 or IL-4 on reconstitution of donor lymphoid cells in congenic murine bone marrow transplantation.

IL-7 and IL-4 are known to influence the growth of cells of the lymphoid lineage. In this study, we investigated the effects of in vivo administration of IL-7 or IL-4 in mice subjected to congenic BM transplant. C57BL/6 Ly5.1+ mice were subjected to TBI, followed by transfer of B and T cell-depleted BM from C57BL/6 Ly5.2+ donor mice. Recipient mice were implanted with 14-day miniosmotic pumps that delivered IL-7, IL-4 or PBS and were examined for reconstitution of lymphoid cells using flow cytometry on different days. We observed no significant difference in the number of splenocytes, thymocytes and PBLs between recipient mice administered with cytokines or normal control mice. However, we observed that IL-4 infusion resulted in appearance of increased numbers of donor CD23+B220+ cells and also donor cells expressing Fc receptors for IgM (Fc micro R) and B220. Since CD23 is present only on mature B cells, our data demonstrate that following BMT, IL-4 treatment results in the development of more mature B cells compared to control mice. Additionally, we observed that IL-7 infusion resulted in significantly decreased expression of donor sIgM+B220+ cells. However, the effects of IL-7 or IL-4 were observed when the cytokines were actively administered and rapidly abated upon cessation of cytokine therapy.

Animals↗

[Studies on red blood cell-mediated immunity of patients with recurrent stromal herpes simplex keratitis].

Assays of red blood cell (RBC) C3b receptor rosette and RBC immune complex (IC) rosette of 67 cases with recurrent stromal herpes simplex keratitis (HSK) were carried out. The results show that the rosette rate of RBC C3b receptor is markedly lowered and that of RBC IC receptor is significantly increased in cases with stromal HSK. In comparisons with the corresponding rates in the control group, there are significant differences (P < 0.01). The roles of RBC-mediated immunity in the immunopathogenesis of HSK were preliminarily discussed.

Adolescent↗

[Study on the reversing effect of tripiperaquine on human multidrug resistant leukemic cell line K562/A02].

K562/A02 is a Cell line with multi-drug resistance established in our laboratory bey long term induction with adriamycin. In this paper, reversal of MDR in K562/A02 cell line by tripiperaquine is reported. The cytotoxicity and intracellular concentration of daunorubicin (DNR) in K562/A02 were measured by MTT colorimetric assay and spectrofluorimetry. The results showed that the sensitivity of K562/A02 to DNR was greatly enhanced by tripiperaquine at 10 micrograms/ml, with an 11-fold increase in cytotoxic activity. The intracellular concentration of DNR in K562/A02 was significantly increased after coincubation with 20 mumol/L tripiperaquine for 3 hours. Our results suggest that tripiperaquine might be used in clinical trial to reverse MDR.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

[Surgical treatment of ascending aortic dissecting aneurysm with Cabrol's operation in 3 patients].

Form Mar. 1993 to Dec. 1994, 3 patients with ascending aortic dissecting aneurysm underwent aneurysmal incision, artificial vessel interposition, aortic valvular replacement and coronary artery transposition as Cabrol's operation. All recovered health discussed. The procedures and techniques were modified on the Cabrol's. Anastomosis of coronary openings with 8 mm Gore-tex tube obtained good match, little tension, and avoided intimal tear around coronary ostia and blood leakage of the anastomosis. We have created a self blood infusion system to stop hemorrhage of vessel graft or anastomosis by a bypass between right atrium and aneurysmal sac around the dacron graft.

Adult↗

[Anti-metastasis gene nm23 expression in buccal cancer studied by immunohistochemistry stain].

The nm23 gene has been proposed as a candidate metastasis-suppressor gene. In this study we used immunohistochemistry stain for polyclone antibody nm23 in 62 cases of buccal carcinoma. The results showed that both the epithelium of mucosa and the duct epithelium of minor salivary gland nearby the tumor were strong positive. The stains on tumor cells were various. 31.0% (9/29) of the cases with lymph-node metastasis were positive while 57.6% (19/33) of those with no lymph-node metastasis positive (P = 0.044). Histologically, 59.4% (19/32) of the cases were positive in Grade I, while 37.5% (6/16) positive in Grade II and 21.4% (3/14) in Grade III (P = 0.048). The positive rate increased with the patients survival time from less than 3 years to 3-5 years and more than 5 years correspondingly, but there was no statistical significance (P = 0.126). The results suggested that the expression of nm23 might be one of the factors influencing the lymph-node metastasis and prognosis of buccal cancer.

Carcinoma, Squamous Cell↗

Expression of p53 gene in oral squamous cell carcinoma and its relation with clinical and pathological parameters and prognosis of patients.

One hundred and eleven cases of oral squamous cell carcinoma (OSCC) were examined for overexpression of p53 protein by using immunohistochemical technique. Association between p53 protein overexpression and clinical and pathological parameters as well as prognosis of patients were also analyzed. p53 protein overexpression was commonly observed (69.4%) in OSCC and may be used as a marker of carcinogenesis of OSCC. The level of p53 protein overexpression is correlated with the lower three and five-year survival rate of OSCC. The presence or absence of p53 overexpression was not correlated with sex, age, site of tumor, size of tumor, degree of differentiation, node status, and clinical stage in OSCC. Single factor COX proportional hazards regression model analysis indicated that there was no significant association between p53 overexpression and prognosis of OSCC. Multivariable COX model analysis failed to establish effective life function or risk rate function. These showed that all the parameters analyzed in this study as well as p53 overexpression were not significant and effective risk factors of prognosis for patients with OSCC.

Carcinoma, Squamous Cell↗

[Experimental study of trachea reconstruction using autogenous soft tissue of chest wall with the stent].

The dog trachea were reconstructed after the trachea resection using the tubule made by autogenous intercostal compound soft tissue, including intercostal muscle, costal periosteum, and pleura, with pedicle of the intercostal vessels. A stent of fine wire was implanted inside of the reconstructed trachea as supporting. The postoperative result in the short period was satisfied, the operative complications, such as anastomotic leakage, granulation, anastomotic stenosis, and stent moving were not common. The tubule design, operative procedure, the postoperative local X-ray and the fiberscopic findings in the dogs were introduced. The study provides experimental evidences for clinical trachea reconstruction.

Animals↗

Rab proteins form in vivo complexes with two isoforms of the GDP-dissociation inhibitor protein (GDI).

GTPases of the Rab family play a key role in the regulation of vesicular transport in eukaryotic cells. Several accessory proteins that regulate their GDP/GTP cycle as well as their subcellular localization have been identified within the past few years. The best known is Rab3A GDP dissociation inhibitor protein (GDI), originally identified as an inhibitor of GDP dissociation from Rab3A, a Rab protein specifically expressed in neuronal and neuroendocrine cells. Recent studies have pointed out a role of Rab3A GDI as a chaperone of several Rab proteins during their cycling between cytosol and membranes and Rab3A GDI has been considered so far as a general regulator of Rab function. However, cDNAs encoding potential isoforms of this protein, called GDI beta and GDI-2, have been recently isolated. In this study, we have characterized cytosolic Rab protein complexes in various cell types and tissues using Mono Q chromatography. We show that in rat brain and in insulin-secreting RINm5F cells, the majority of Rab proteins are complexed with Rab3A GDI. In contrast, in Chinese hamster ovary cells, they are mainly complexed to a protein that we have identified as GDI beta. In rat liver cytosol, Rab proteins form complexes with both isoforms. We also show that the proportion of Rab proteins complexed with either isoform depends on the relative abundance of Rab3A GDI and GDI beta in the cytosol. These findings suggest that GDI isoforms are either redundant or could be involved in the fine control of Rab function.

Amino Acid Sequence↗

Interleukin 2 mediates p72syk activation in peripheral blood lymphocytes.

The ability of interleukin 2 (IL-2) to stimulate p72syk activity in intact porcine peripheral blood lymphocytes was examined. We demonstrated that IL-2 activated p72syk in a time- and dose-dependent manner, for which its peak time and maximum responsive dose were 5 min and 100 U/ml, respectively. This activation was observed only in cytosolic fractions and not in membrane ones. However, IL-2 failed to induced calcium mobilization. Moreover, IL-2-inducible p72synk activation was not affected when extra- intracellular calcium was depleted. These data suggest that the IL-2 signaling pathway through p72syk in peripheral blood lymphocytes is different, at least in part, from other agonists, such as concanavalin A in polymorphonuclear neutrophils which can trigger both the activation of p72syk and intracellular calcium mobilization.

Animals↗

A unique antigenic determinant on collagen II closely associated with age related abnormal modification.

During aging, a variety of proteins undergo a non-enzymatic modification, such as oxidation, attachment of lipid peroxide, and glycation. In particular, the long-lived extracellular matrix proteins in connective tissue may be common targets for this kind of modification which, in turn, is involved in the pathogenesis of age related diseases. In the present study, we demonstrate that the age related modification on collagen II generates (a) new epitope(s). Furthermore, we established an immunochemical assay which is specifically suited to monitor the extent of abnormal modification of collagen II.

Adolescent↗

Purification and characterization of a protein-tyrosine kinase p72syk from porcine spleen.

We have succeeded in purifying p72syk, a non-receptor-type protein-tyrosine kinase carrying high susceptibility to proteolysis [Taniguchi, T., Kobayashi, T., Kondo, J., Takahashi, K., Nakamura, H., Suzuki, J., Nagai, K., Yamada, T., Nakamura, S. and Yamamura, H. (1991) J. Biol. Chem. 266, 15790-15796] from porcine spleen. The purification procedure involves a sequential column chromatography, following extraction with 0.5 M NaCl from spleen homogenate, on phosphocellulose, Sephacryl S-200, heparin-Sepharose CL-6B, Mono Q and Mono S. SDS/PAGE of the final purified sample revealed a 72-kDa protein band with about 95% purity and immunodepletion analysis showed immunological cross-reactivity with anti-p72syk antibody which does not recognize ZAP-70. It was purified approximately 3000-fold with an overall yield of 0.54% according to [Val5]angiotensin II phosphorylation activity and the specific activity of the final sample (30 nmol phosphate.min-1.mg protein-1) was relatively lower than that of the 40-kDa kinase, a catalytic fragment of p72syk which lacks two src homology regions 2 domains. The p72syk had an autophosphorylation activity that was performed by intramolecular catalysis accompanied by a phosphate exchange reaction, and could efficiently phosphorylate tubulin, myelin basic protein and H2B histone. Employing [Val5]angiotensin II as a substrate, the apparent Km value for the peptide was 0.91 mM and that for ATP was 0.48 microM. Mn2+, Mg2+ and Co2+ were effective divalent cations and optimum pH was around 8.0-8.5 for the expression of the activity. These results suggest that the purified p72syk may exist as a less active form compared with the 40-kDa kinase and that the part of p72syk containing two src homology region 2 domains may participate in the regulation of its activity though the enzymic character is quite similar to that of the 40-kDa kinase.

Amino Acids↗

Pharmacokinetics, biodistribution and tumor localization of two anti-human B-cell chronic lymphocytic leukemia monoclonal antibodies and their F(ab)'2 fragments in a xenograft model.

We investigated the pharmacokinetics, biodistribution and tumor localization of intravenously injected Dal B01 and Dal B02, two monoclonal antibodies (MoAbs) directed against tumor associated antigens on human chronic lymphocytic leukemia (CLL) B cells, and their F(ab)'2 fragments in nude mice bearing xenografts of the human B cell CLL line D10-1. More of the percentages of the injected dose (% ID) of these two MoAbs and their F(ab)'2 fragments specifically localized in the tumor xenografts than in normal tissues. Compared to intact MoAbs, their F(ab)'2 fragments had lower % ID in tumors and were cleared from circulation faster. Well-defined tumor images were obtained at 24 and 48 h after administration of [131I]Dal B02 F(ab)'2 fragment and at 96-192 h after administration of [131I]Dal B02. A comparison between intravenous and intraperitoneal routes of administration of [131I]Dal B02 did not reveal any difference in the localization of % ID in tumor or normal tissues.

Animals↗

Primary structure of apoB-100.

Apolipoprotein B-100 (apoB-100) is the major protein in low-density lipoprotein (LDL) and contains the ligand for binding LDL to its cell surface receptor. Lipoprotein [a] (Lp[a]) is a lipoprotein that consists of LDL and apolipoprotein [a] (apo[a]). The primary structure of apoB-100 has been determined by a combination of recombinant DNA and protein sequencing methods. Using high-performance liquid chromatographic techniques, we have identified sulfhydryl and disulfide groups of apoB-100 from LDL. Sixteen of the 25 cysteine residues in apoB-100 exist in disulfide form. All 14 cysteine residues within the N terminal end of apoB-100 are linked in disulfide bridges. Using the fluorescent sulfhydryl probe, 5-iodoacetoamidofluoresceine, two free sulfhydryls of apoB-100 on LDL were identified at positions 3734 and 4190. Based on its differential susceptibility to trypsin, apoB-100 can be divided into five domains: domain 1 (residues 1-1000), largely trypsin-releasable (TR); domain 2 (residues 1001-1700), alternating TR and trypsin non-releasable (TN); domain 3 (residues 1701-3070), largely TN; domain 4 (residues 3071-4100), mainly TR and mixed; and domain 5 (residues 4101-4536), almost exclusively TN. Based on our data, we propose that the structure of apoB-100 in LDL is probably an elongated form that wraps around the LDL particle, and that Cys3734 of apoB-100 may be the cysteine residue linked to a cysteine of apo[a].

Apolipoprotein B-100↗

Immunoreactivity, stability, pharmacokinetics and biodistribution of a monoclonal antibody to human leukemic B cells after three different methods of radioiodination.

Dal B02, a murine monoclonal antibody against human chronic lymphocytic leukemia (CLL) was radioiodinated using chloramine T (Chl.T), Bolton-Hunter (B-H) or N-succinimidyl-p-iodobenzoate (PIB). The preparations had comparable radiochemical purity (> 97%) and immunoreactive fraction (65-80%) but the Chl.T-based product was most susceptible to deiodination and loss of immunoreactivity. After i.v. injection into CLL-xenografted nude mice, the preparations had identical patterns of clearance from the blood but the PIB-based product led to more radioactivity in liver and spleen and less in the thyroid compared to the other preparations. The Chl.T-based product showed loss of immunoreactivity in circulation and less tumor-localized radioactivity 168 h after administration. The differences between the B-H-based and PIB-based products were less impressive than between PIB-based and Chl.T-based products.

Animals↗

Intracellular calcium dependent activation of p72syk in platelets.

We previously demonstrated that thrombin-induced activation of p72syk was independent of intracellular Ca2+ elevation in platelets. However, our previous studies also demonstrated that activation of platelets by ionophore A23187 results in a dramatic increase in tyrosine phosphorylation of several cellular proteins. In the present study, we investigated the effect of Ca2+ elevation on the activity of p72syk. When washed porcine platelets were stimulated with ionophore A23187 and the activity of p72syk was assessed by means of an immunoprecipitation kinase assay, A23187 caused a time- and dose-dependent increase in the specific activity of p72syk. In addition, pretreatment of platelets with both aspirin and ADP scavengers or chelation of extracellular Ca2+ by EGTA had no effect on the A23187-induced activation of p72syk. These results indicate that A23187-induced activation of p72syk is independent of the formation of endoperoxide/thromboxane A2, released ADP and extracellular Ca2+, suggesting the existence of a novel pathway for activation of p72syk. Furthermore, evidence is presented which indicates a synergistic effect of A23187 and thrombin on the activation of p72syk, and an inhibitory effect of pretreatment with phorbol 12-myristate 13-acetate, a protein kinase C activator, on the activation of p72syk induced by either A23187 or thrombin.

Animals↗