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Biomedical subjects

J C Zhang

Publications and source records attributed to J C Zhang.

At least 37 records · Page 2Linked to original sources
PubMed1996

Human fibroblasts downregulate plasminogen activator inhibitor type-1 in cultured human macrovascular and microvascular endothelial cells.

We have previously reported that plasminogen activator inhibitor type-1 (PAI-1) expression in endothelial cells (ECs) can be modulated differently by smooth muscle cells depending on their origin. Human pulmonary artery smooth muscle cells (HPASMCs) strongly downregulated PAI-1 expression in ECs. Fibroblasts (FBs) are another cell type that could come in close contact with ECs. Therefore, it was the aim of this study to investigate whether FBs could also influence the fibrinolytic potential of ECs. As in the case of HPASMCs, PAI-1 antigen produced by human umbilical vein ECs (HUVECs) cocultured with human skin FBs (HSFBs) was significantly lower as compared with the sum of PAI-1 secreted by the respective cell types cultured separately. Not only HUVECs but also human skin microvascular ECs (HSMECs) responded in a dose-dependent way to serum-free conditioned media (CM) from HSFBs from one individual donor. Similar results were obtained when CM from HSFBs from four other individual donors were used. PAI-1 mRNA decreased in HUVECs incubated for 6 hours with HSFB-CM to 24% to 55% of control, depending on the preparation of HSFBs used. A significant PAI-1 downregulatory effect was only observed when CM from low-passage HSFBs (up to passage no. 5) was used, whereas no reduction in EC PAI-1 production was observed with CM obtained from HSFBs in passage no. 8. This PAI-1 downregulatory activity present in HSFB-CM was heat-labile and had a molecular mass of approximately 5 kD. When CM from HPASMCs was analyzed in the same way, an almost identical elution profile was found. In conclusion, our data showed that FBs can decrease the expression of PAI-1 in ECs. Such an effect could be operative during wound-healing and at other capillary sites where FBs could render ECs profibrinolytic, thereby facilitating processes requiring an increase in proteolytic activity such as EC migration and proliferation.

Biological Factors↗
PubMed1995

Growth and fibrinolytic parameters of human umbilical vein endothelial cells seeded onto cardiovascular grafts.

It was the aim of this study to investigate possible effects of biomaterials used to produce vascular grafts on the fibrinolytic system of endothelial cells. Therefore growth conditions for human umbilical vein endothelial cells on polytetrafluoroethylene and on polyurethane were optimized. Tissue culture polystyrene was used as a control material. We could demonstrate that precoating of the materials with fibronectin significantly increased the growth rate of human umbilical vein endothelial cells on these materials. Furthermore, we showed that human umbilical vein endothelial cells grown on polytetrafluoroethylene or polyurethane released more plasminogen activator inhibitor-1 and tissue type-plasminogen activator into the conditioned media than did human umbilical vein endothelial cells grown on tissue culture polystyrene. Human umbilical vein endothelial cells cultured on polytetrafluoroethylene also deposited more plasminogen activator inhibitor-1 into the extracellular matrix than did control cells grown on tissue culture polystyrene. Our results give evidence that human umbilical vein endothelial cells grown on two biomaterials used to construct vascular grafts, namely polytetrafluoroethylene and polyurethane, produce tissue-type plasminogen activator as well as plasminogen activator inhibitor-1, two major components of the fibrinolytic system also expressed by endothelial cells in vivo. In conclusion, our data suggest that endothelial cells grown on vascular grafts show functional integrity concerning their fibrinolytic system, which in turn might contribute to reduce the thrombogenic properties of the graft material.

Biocompatible Materials↗
PubMed1994

Alterations of fibroblast metabolism in early ligature-induced periodontitis in the cynomolgus monkey.

Cellular and biochemical observations were made of fibroblasts harvested from ligature-induced periodontitis and treated gingivitis areas in four adult female cynomolgus monkeys (Macaca fascicularis) to define the changes that occur in the early periodontitis lesion. Compared with fibroblasts from the treated sites, fibroblasts from the diseased areas had a significantly higher rate of proliferation, produced about two-thirds the amount of total protein and collagen, and failed to respond to TGF-beta, which normally stimulates extracellular matrix formation in mesenchymal cells. The diseased cells were also deficient in the activity of poly(ADP-ribose) synthetase, an enzyme involved in the repair of DNA breaks such as occur from the insults of superoxide and other active radicals present in inflamed areas. Although the precise nature of these biochemical defects is not fully elucidated, they may have an important bearing on chronic periodontitis cases with a "downhill" course.

Animals↗
PubMed1993

[The biologic character of gingival fibroblasts from normal and periodontitis sites]

Histological and clinical studies have found that periodontal ligament fibroblasts can produce connective attachment,while gingival fibroblasts cannot yet.The mechanism for gingival fibroblasts losing their ability of new attachment is unknown.We investigated the function of colagen synthesis by gingival fibroblasts from periodontitis sites,and normal sites and their response to TGF-beta,and Nicotinamide and Lactate,the inhibitors of poly(ADP-ribosyl)ation.We found that gingival fibroblasts from diseased sites produce much less collagen than from control sites (73.6+/-8.8vs.107.1+/-12.3,P<0.01),and these cells show unresponsive to TGF-beta,Nicotinamide and Lactate on collagen synthesis.These results may partly explain why gingival fibroblasts from periodontitis site lose their ability of new attachment.

Journal Article↗
PubMed1993

[Defects in insulin binding, internalization and degradation of monocytes from patients with non-insulin-dependent diabetes mellitus].

A14-125I-monoiodoinsulin binding to, internalization into, and degradation inside human circulating monocytes, a cell type widely used for insulin receptor studied, from normal(32) and weight, age-matched NIDDM(31) subject were studied. The specific insulin binding, internalization and degradation were decreased in the cells from NIDDM compared to that in the cells from normal subjects. Scatchard plot analysis of these group data reveal that cells from the normal control subject contain 28,000 receptor sites per cell, while monocytes from the NIDDM patients contain 15,000 sites per cell. These results indicate that the decreased abilities of insulin binding, internalization and degradation of target cells may play a role in the cellular resistance to insulin that occurs in the NIDDM.

Adult↗
PubMed1992

Combined metformin-sulfonylurea treatment of patients with noninsulin-dependent diabetes in fair to poor glycemic control.

The effect of metformin treatment was studied in 13 patients with noninsulin-dependent diabetes mellitus (NIDDM), whose fasting plasma glucose concentration was greater than 10 mmol/L with maximal sulfonylurea doses. Patients were studied before and 3 months after receiving 2.5 g/day metformin. The fasting plasma glucose concentration (12.4 +/- 0.8 vs. 8.8 +/- 0.7 mmol/L), mean hourly postprandial plasma glucose concentration from 0800-1600 h (14.0 +/- 1 vs. 9.4 +/- 0.9 mmol/L), and glycosylated hemoglobin level (12.3 +/- 0.6% vs. 9.0 +/- 0.6%) were all significantly (P less than 0.005-0.001) lower after the administration of metformin. The improvement in glycemic control was associated with a 24% increase (P less than 0.05) in insulin-stimulated glucose uptake during glucose clamp studies and a 16% decrease in basal hepatic glucose production (P less than 0.05). Mean hourly concentrations of plasma insulin (411 +/- 73 vs. 364 +/- 73 pmol/L) and FFA concentrations (440 +/- 31 vs. 390 +/- 40 mumol/L) were also lower after 3 months of metformin treatment. However, neither insulin binding nor insulin internalization by isolated monocytes changed in response to metformin. Finally, plasma triglyceride, very low density lipoprotein triglyceride, and very low density lipoprotein cholesterol were significantly decreased (P less than 0.01-0.001), and high density lipoprotein cholesterol was significantly increased (P less than 0.001) after metformin treatment. Thus, the addition of metformin to sulfonylurea-treated patients with NIDDM not in good glycemic control significantly lowered fasting and postprandial plasma glucose concentrations, presumably due to the combination of enhanced glucose uptake and decreased hepatic glucose production. Since the dyslipidemia present in these patients also improved, the results suggest that metformin may be of significant clinical utility in patients with NIDDM not well controlled with sulfonylurea compounds.

Blood Glucose↗
PubMed1991

[Desensitive treatment with positive allergens in acupoints of the head for allergic rhinitis and its mechanism].

Desensitive treatment of 102 cases of allergic rhinitis caused by allergens has been carried out using acupuncture endermic points of the head with the extract of positive allergen (or allergens). After two courses of the treatment, the extract of allergens was taken again to make intradermal injection. Diameter of redness and swelling on the skin was significantly reduced in comparison with that before the treatment (P less than 0.01). Cell mediated and humoral immunity of the patients tended to be normal. These cases were followed up for 2 years. 72.18% of the cases had significantly curative effect; 23.56% turned better. Comparison of curative difference of this group with the other two control groups was significant (P less than 0.01). Therefore, this method is of considerable clinical value and worth popularizing in treatment of allergic rhinitis.

Acupuncture Points↗
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↗
PubMed1990

[Long-term observation and treatment of 30 cases of intrathoracic sarcoidosis].

The results of a long-term follow up for an average of 7.3 years (ranged from 6 months to 22 years) on 30 cases of intrathoracic sarcoidosis are reported. The course of the disease was more than 2 years in 90% (27/30), and less than 2 years in 10% (3/30). At the beginning of the observation, 53.3% (16/30) of the patients were in stage I, 36.7% (11/30) in stage II, and 10% (3/30) in stage III. But at the end of follow up, 6 cases had spontaneous remission, 9 had been cured, 6 were in stage II and 9 in stage III. Nor was in stage I or died. According to these results, the treatment of intrathoracic sarcoidosis is discussed.

Adult↗
PubMed1989

[Preliminary report on the serum level of pancreatic polypeptide in patients with chronic bronchitis and bronchial asthma during attacks].

Serum pancreatic polypeptide (pp) both at fasting state and after giving compound Datura stramonium suppositories were measured by RIA in 21 cases with bronchial asthma and 16 cases with chronic bronchitis during attacks. Comparing with matched control groups the levels of pp in asthma and chronic bronchitis were significantly higher (P less than 0.05 & 0.01) After using compound Datura stramonium, the levels decreased. The results showed serum pp is an useful biochemical index.

Adolescent↗
PubMed1987

Bombesin binding and biological effects on pancreatic acinar AR42J cells.

The effects of bombesin on amylase release and the receptor binding of 125I-[Tyr4]bombesin in the rat pancreatic acinar carcinoma cell line AR42J were examined. Bombesin-like peptides stimulated amylase release from AR42J cells in a dose-dependent manner; a maximal 2-fold stimulation occurred at a bombesin concentration of 300 pM. Binding of 125I-[Tyr4]-bombesin to AR42J cells was specific, saturable and temperature dependent. The relative potencies with which various structurally related peptides stimulated amylase release correlated well with their relative abilities to compete for the bombesin receptor.

Amylases↗