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Biomedical subjects

C G Ruan

Publications and source records attributed to C G Ruan.

13 recordsLinked to original sources
PubMed1992

Increase in plasma thrombomodulin and decrease in plasma von Willebrand factor after regular radiotherapy of patients with cancer.

In this study, we investigated plasma levels of thrombomodulin (TM) and von Willebrand factor (vWF) in 51 patients suffering from cancer or tumor undergoing 60 cobalt radiotherapy. Plasma TM and vWF antigen were measured by immunoradiometric assay and ELISA, respectively. During radiotherapy, an increase in plasma TM in patients was observed, which was radiation-dose dependent and there was a positive correlation between plasma TM level and radiation doses. However, the level of plasma vWF in the patients was decreased during radiotherapy and there was an inverse correlation between the amount of plasma vWF and radiation doses. Our data indicate that plasma TM is an useful molecular marker for early detection of radiation injury to endothelial cells in patients undergoing radiotherapy.

Adolescent↗
PubMed1992

Thrombus imaging in dogs with a monoclonal antibody (SZ-51) specific for activated human platelets.

To specifically detect the localization of thrombus in vivo, we prepared a monoclonal antibody (McAb) SZ-51 specific for an alpha-granule membrane protein (GMP-140) on the surface of activated human platelets. The thrombus binding rate in vitro was 80 +/- 5% for 131I-SZ-51 and 4.4 +/- 0.5% for 131I-nonimmune IgG. Owing to the crossreaction of McAb SZ-51 with the activated platelets of dogs, thrombus in the femoral artery and vein of dogs was formed and imaged with single photon emission computerized tomography (SPECT). The ratio of thrombus to blood radioactivity (T/B) was 2.1, 4.8, 14.0 and 18.0 at 1, 2, 3 and 4 hours after injection of 131I-SZ-51 (0.6 mCi, 50 micrograms) into the arterial thrombus respectively, while the T/B ratio was 1.7, 2.2, 5.3 and 8.0 for venous one. The injection of 131I-nonimmune IgG at the same doses yielded a T/B ratio of 1.2 +/- 0.3 at each time period for both arterial and venous thrombi. These findings were in good agreement with the counting of removed thrombi 24 hours after the injection of radiotracer. The ratio was 21.7 and 2.6 for the 131I-SZ-51 in the arterial and venous thrombus, respectively. However, there were only 1.48 and 1.6 for the 131I-nonimmune IgG. These results indicate the great potentiality of McAb SZ-51 in application to detection of thrombi in vivo.

Animals↗
PubMed1992

Inhibitory effects of tetramethylpyrazine on platelets during cardiopulmonary bypass and arterial thrombus formation in dogs.

The corrected platelet count at the end of cardiopulmonary bypass (CPB) in nontreated dogs fell to 56.7% of the pre-operative level, while in tetramethylpyrazine (TMP, 10 mg.kg-1, iv)-treated dogs it fell to 82.8%. The number of alpha-granule membrane protein (GMP-140) which was expressed on the surface of activated platelets increased from the outset of CPB and reached the peak at the end of CPB in control dogs. But the number of GMP-140 molecules did not increase significantly throughout the operative procedure in TMP-treated dogs. In experimental thrombosis in dogs, the weight of the thrombus reduced to 23% of that in controls and the radioactivity ratio between the thrombus and blood was only 29% of that in controls at 4 h after iv injection of 125I-SZ-51 (a monoclonal antibody against GMP-140). These results indicate that TMP inhibits the platelet activation during CPB and arterial thrombosis.

Animals↗
PubMed1992

[Molecular pathology of inherited Glanzmann's thrombasthenia. Report of 11 cases].

Glycoprotein IIb-IIIa (GPIIb-IIIa) concentration was studied in 11 patients with Glanzmann's thrombasthenia (GT) with sensitive Western blotting technique. 7 patients with severe GPIIb-IIIa deficiency (less than 10% of the normal) were designated as type I (64% of patients), 2 patients with moderate GPIIb-IIIa deficiency (10-25% of the normal) as type II (18%) and 2 patients with GPIIb-IIIa 40-100% of the normal as variants (18%). Southern Blotting was used to analyze the GPIIb and GPIIIa genes in the 11 patients. The results showed that there were no major deletions or insertions in either the GPIIb or GPIIIa genes. However, a small change in GPIIb gene was demonstrated in two sibling patients and the abnormality of GPIIIa gene was found in another two patients. These observations combined with those from literature provide a basis for discussing the molecular pathology of Glanzmann's thrombasthenia.

Adolescent↗
PubMed1992

Effect of new-breviscapine on fibrinolysis and anticoagulation of human vascular endothelial cells.

Cultured confluent human umbilical vein endothelial cells were incubated with new-breviscapine (NB), a flavonoid consisting of 4-OH-scutellarin-7-O-glucuronide (C33H30O18) and FeCl3, MgCl2, and CaCl2, which is first extracted from Erigeron breviscapus (Vant) Hand-Mazz in China, 0, 6.25, 12.5, 25, 50, 100, and 1,000 micrograms.ml-1. The releases of tissue-type plasminogen activator (t-PA), and epoprostenol (Epo) from endothelial cells were stimulated by NB, but no significant effect of plasminogen activator inhibitor (PAI) activity was seen. NB 25-1,000 micrograms.ml-1 induced a production of thrombomodulin (TM) within the cells, an expression of TM on the surface of the cells, and a release of TM from the cells. Our data provide a new evidence that NB is a stimulant to fibrinolysis and anticoagulation of endothelial cells.

Anticoagulants↗
PubMed1990

New method to quantitate platelets adhered on biomaterials using monoclonal antibodies to human platelet membrane glycoprotein SZ-21.

This study developed a new technique to quantitate platelets adhered on biomaterials surfaces in vitro, based on a surface phased radioimmunoassay using a monoclonal antibody SZ-21, directed specifically against the membrane glycoprotein complex IIIa of human platelets. In vitro perfusion is performed in system which consists of testing tubes and infusion pump. After 5 minutes perfusion with fresh ACD anticoagulated human whole blood at 2,000s-1 platelets deposition on surface precoated with proteins determined using anti-human platelet antibody (125 I-SZ-21) are 4,173 +/- 932 (Albumin), 59,032 +/- 25,554 (Fibrinogen), and 71,253 +/- 11,484 (Collagen). Meanwhile, platelets adhered on surfaces of four polymers were determined (platelet/mm2): 19,493 +/- 2,050 (Silicone), 48,193 +/- 4,055 (Polytetrafluoroethylene), 50,375 +/- 8,675 (Polyvinyl chloride) and 101,906 +/- 5,916 (Polyethylene). These results were confirmed by SEM. This method is not only applied for evaluating rapidly and reliably blood compatibility of biomaterials in vitro, but will be used at basic study for interaction of blood materials.

Antibodies, Monoclonal↗
PubMed1987

Studies on monoclonal antibodies against human platelets--a monoclonal antibody to human platelet glycoprotein I--SZ-2.

A monoclonal antibody, SZ-2, reacts specifically on human platelets and megakaryocytes. The platelets from 10 normal donors are bound to 15,200 +/- 4,100 SZ-2 molecules/platelet. The antigen recognized by SZ-2 is chymotrypsin-sensitive but neuraminidase-insensitive, and has been identified as glycoprotein Ib (GPIb) by an affinity chromatography technique. SZ-2 is different from other monoclonal antibodies to GPIb. It inhibits not only platelet aggregation induced by ristocetin, but also platelet aggregation induced by collagen (type I) and by PAF. SZ-2 also inhibits platelet serotonin and beta-thromboglobulin release in response to these stimuli.

Antibodies, Monoclonal↗
PubMed1987

A murine antiglycoprotein Ib complex monoclonal antibody, SZ 2, inhibits platelet aggregation induced by both ristocetin and collagen.

A new monoclonal antibody (MoAb), SZ 2, reactive with the human platelet glycoprotein Ib complex has been produced by the hybridoma technique. SZ 2 immunoprecipitated the components of the glycoprotein Ib complex, glycoprotein Ib and glycoprotein IX, from Triton-X-100-solubilized, periodate-labeled platelets. Western blot analysis indicated that the epitope for SZ 2 was on the alpha-subunit of glycoprotein Ib. Scatchard analysis of SZ 2 binding to formaldehyde-fixed, washed platelets revealed a single class of binding sites with Kd = 6.6 +/- 3.3 X 10(-10) mol/L and 15,200 +/- 4,100 binding sites per platelet (mean +/- SD, n = 10). Intact antibody and its purified (Fab')2 fragments not only inhibited the ristocetin-dependent binding of von Willebrand factor to platelets and ristocetin-induced platelet agglutination but also inhibited platelet aggregation induced by Type I collagen and platelet-activating factor (PAF). SZ 2 inhibited platelet serotonin and beta-thromboglobulin release in response to these stimuli and also platelet thromboxane A2 formation in response to ristocetin and collagen. SZ 2 was without effect on platelet aggregation or release in response to other platelet stimuli such as ADP, thrombin, or arachidonic acid. The inhibition by SZ 2 of collagen- and PAF-induced platelet aggregation is surprising in that Bernard-Soulier syndrome platelets, which lack the glycoprotein Ib complex, respond normally to both these stimuli. SZ 2 was unreactive toward Bernard-Soulier syndrome platelets, as evaluated by fluorescence-associated cell sorting, and had no effect on the collagen- and PAF-induced aggregation of Bernard-Soulier syndrome platelets. The combined results suggest that the inhibition by SZ 2 of collagen- and PAF-induced aggregation of normal platelets is steric and are consistent with the glycoprotein Ib complex and the platelet collagen and PAF receptor(s) being adjacent in the human platelet plasma membrane.

Animals↗