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Biomedical subjects

Z Yang

Publications and source records attributed to Z Yang.

At least 415 records · Page 23Linked to original sources
PubMed1999

[Study on the prevention of insulitis and diabetes by complete Freund's adjuvant in NOD female mice].

The degrees of insulitis, the incidence of diabetes, and the counts of alpha,beta and delta cells in islets were studied by morphological method and avidin-biotin complex immunohistochemical method in complete Freund's adjuvant(CFA) or normal saline(NS)-treated non-obese diabetic(NOD) female mice. The results showed: The incidences of in-insulitis and the scoring means were significantly lower in CFA-treated mice than those in NS-treated ones; none of 5 CFA-treated mice and 3 out of 5 NS-treated ones developed diabetes. The positive rates of alpha, and delta cells were significantly lower in CFA-treated mice than those in NS-treated ones, but the positive rate of beta cell was significantly higher in CFA-treated mice than that in NS-treated ones. The correlations were found among the scores of insulitis and the positive rates of alpha, beta, delta cells in islets (r alpha = 0.475, r beta = -0.878, r delta = 0.869). The results indicate that CFA may lessen the degrees of insulitis and the incidence of diabetes. Its effects might be related to lessen the damage of beta cell in islets.

Animals↗
PubMed1999

[Study on regulators of the cell cycle in cutaneous squamous cell carcinoma].

In order to investigate the relationship between the regulators of cell cycle and cutaneous squamous cell carcinoma(SCC), we used an immunohistochemical staining technique to examine the expression of cyclin D1, p16 and Rb in the paraffin embedded skin cancer tissues of 30 patients with SCC. The positive percentage of cyclin D1, CDK4, p16 and Rb was 66.7%, 53.3%, 33.3%, and 36.7%, respectively. The overexpression of cyclin D1 and CDK4 could be observed frequently in low grade of differentiated cells, especially in marginal cells of the cancer nest. The results indicate that the aberrant expression of positive and negative regulators of the cell cycle may be involved in the carcinogenesis and evolution of SCC.

Carcinoma, Squamous Cell↗
PubMed1999

[Mutation and expression of p16 in human ovarian neoplasms].

OBJECTIVES: To detect mutation and expression of p16 in human ovarian neoplasms and to understand the relations between p16 and development of ovarian neoplasms. METHODS: Polymerase chain reaction-single strand polymorphism analysis and immunohistochemistry were respectively used to detect mutations in exon 1 and 2 and protein expression in 14 patients with ovarian neoplasms. Metastasis tissue of 5 mentioned patients were screened at the same time. RESULTS: No expression of p16 was found in 7 ovarian neoplasm tissues. No mutation in exon 1 of p16 was found in any patient tissues, but mutations in exon 2 were found in 4 patients tissues and expression of p16 was not found in 2 of them. There was correspondence between primary focus and metastasis in either gene mutation or protein expression. CONCLUSIONS: Inactivation of p16 may be involved in the development of ovarian neoplasms. Gene mutation is a kind of inactivation. Alterations of p16 probably occur before metastasis.

Cyclin-Dependent Kinase Inhibitor p16↗
PubMed1999

[Interaction of cell adhesion to materials in tissue engineering].

OBJECTIVE: To investigate the adhesive interactions of cells with materials and the effects of material properties on cell adhesion in tissue engineering. METHODS: By looking up the recent literatures dealt with adhesive interactions of cells with materials and reviewing previous work on the adhesion of tissue-derived cells to materials. RESULTS: The adhesion characteristics of cells to materials not only depend on the nature of materials, including bulk and surface properties, surface modification, surface morphology, net charge, porosity and degradation rate, but also on the expression of cell surface molecules and their interaction with the material. CONCLUSION: The quantitative measure and biophysical mechanisms of cell adhesion to materials might be very important in tissue engineering.

Biocompatible Materials↗
PubMed1999

[Ceramic-like xenogeneic bone combining with bone marrow].

OBJECTIVE: This experimental study was aim to investigate the osteogenesis of ceramic-like xenogeneic bone (CXB) combining with bone marrow (BM). METHODS: The CXB combining BM was implanted into the sacrospinalis muscle of rabbits, and CXB implanted alone was used as control. Eighteen Japanese rabbits with long ear were used. The size of CXB was 5 mm x 5 mm x 5 mm, and the implanted materials were taken out at 2, 4, 8, 12, 16 and 24 weeks after implantation. The histological and histochemical characteristics were investigated. RESULTS: There existed cartilage and new bone in the groups of CXB combining BM in 2 weeks. Later, be cartilage turned out to the bone and in eight weeks the medullary cavity appeared. However, as the time went on, new bone formation increased and typical osteogenesis could be found. While in the groups of CXB alone, no formation of new bone or cartilage was found. CONCLUSION: The implantation of CXB combined with BM could result in new bone formation in the way of osteoconduation, osteoinduction, and providing, osteoblasts or chondroblasts. It could be an ideal bone substitute, and its clinical use in future seemed very hopeful.

Animals↗
PubMed1999

[The influential factors in using cadmium reduction method for measurement of the stable products of NO--nitrates and nitrites].

To establish an efficient assay method for detecting nitric oxide indirectly, we compared the effects of cadmium filing, 5 mmol/L and 80 mmol/L copperized cadmium filing on the measurement of nitrates and nitrites (the stable products of NO) using the cadmium reduction method. The results demonstrated that cadmium filing was the most efficient cadmium preparations (P < 0.001). It's mean reduction rate was 96%, and it showed stronger reduction effectiveness in deproteinization cell culture media. The results indicated that cadmium filing has strong anti-interference capacity in biological fluid. We recommend the cadmium filing reduction method because it is simple, practical, inexpensive, highly efficient and can be performed in ordinary laboratories.

Aorta↗
PubMed1999

[Cell infiltration in nasal polyps and it's pathological significance].

OBJECTIVE: To study the relation between inflammatory cells infiltration in nasal polyp tissues and it's pathogenesis. METHOD: Nasal mucosa from 10 normal individual and 4 patients of nasal polyps were studied with immunohistochemical technique and histopathologic examination. RESULT: The number of eosinophils, CD68 positive cells and monocytes was significantly higher (P < 0.05) in nasal polyps tissues than in the normal controls. CONCLUSION: Infiltration of inflammatory effector cells such as eosinphils and chronic inflammatory changes of the nasal mucosa might play a role in nasal polyps sprouting.

Antigens, CD↗
PubMed1999

[Study of the relation between MMP2, MMP9 and nasopharyngeal carcinoma].

OBJECTIVE: To evaluate the role of matrix metalloproteinase (MMP) in the invasion and metastasis of nasopharyngeal carcinoma (NPC). METHOD: Twenty-six cases of NPC were studied by immunohistochmical method using monocolonal antibody to MMP2 and MMP9. RESULT: It was showed that there were significantly correlation between MMP2 or MMP9 and the invasion and metastasis of NPC. The positive rate of MMP2 and MMP9 were higher in NPC with cervical lymph node involvement than that of no cervical lymph node involvement. And they were lower in well differentiated NPC than poorly differentiated NPC. CONCLUSION: The results indicate that MMP2 and MMP9 may play a critical role in assisting carcinoma cell to degrade basement membrane to invade surrounding tissues and to form metastatic colonies in lymph nodes.

Adult↗
PubMed1999

[Studies on human nasal cycle with acoustic rhinometry].

OBJECTIVE: The aim of this article was to study the classifications and characteristics of nasal cycle of adult and children and the influence of pathological state of nasal mucosa on nasal cycle with acoustic rhinometry. METHOD: We examined the nasal cycle of 16 healthy adults, 11 healthy children and 14 patients with bilateral nasal obstruction. Acoustic rhinometry was performed every 30 minutes (20 minutes in children) over 4-8.5 hours to determine minimum cross-sectional area of nasal cavity (MCA) and nasal cavity volume (NV) which were used as indices of nasal patency. RESULT: Nasal cycles were observed in all subjects. Classical nasal cycle was most commonly observed in healthy adults and patients with nasal diseases. In healthy children, in concert nasal cycle was the most common type. The distribution of the healthy adults and patients with nasal diseases between the cycle categories was not statistically significant different (P > 0.05), the mean periodicity of the cycle was no significantly different between these two groups (P > 0.05). The mean alteration amplitude of nasal cycle of healthy adults was significantly longer than that of patients with nasal diseases (P < 0.01). The distribution of the healthy children and the healthy adults between the cycle categories was significantly different (P < 0.01), the mean periodicity of the cycle of healthy children was distinctively shorter than that of healthy adults (P < 0.01). CONCLUSION: The above results illustrated that nasal cycle exists as central control and local modulation. In healthy children, in concert nasal cycle was most commonly observed and this may be related with the immature condition of their autonomic nervous system.

Adult↗
PubMed1999

[A study on adhesive properties of transformed human embryonic tendon cells to PLA and PLGA].

To study the adhesive properties of transformed human embryonic tendon cells (THETCs) to polylactic acid(PLA) and polylactic-co-glycolic acid 85/15 (PLGA 85/15), the adhesive mechanical properties of single THETCs to PLA films (average thickness 18.6 microns) and PLGA 85/15 films (average thickness 17.3 microns) were measured by means of micropipet aspirating technique. The rsults showed that the attachment rate and adhesive force for two polymer groups(PLA precoated with bovine serum albumin (BSA) and PLGA 85/15 precoated with BSA) were significantly lower than those for two control groups(PLA and PLGA 85/15), respectively, while the attachment rate and adhesive force for other two polymer groups (PLA precoated with poly-D-lysine (PDL) and PLGA 85/15 precoated with PDL) were significantly higher than those for two control groups, respectively, and that the adhesive properties of THETCs to PLGA 85/15 films were better than those of THETCs to PLA films. These demonstrate that BSA can inhibit THETCs attachment to polymer, and PDL can promote THETCs attachment to polymer, and suggest that PLGA 85/15 films were better than those of THETCs to PLA films. These demonstrate that BSA can inhibit THETCs attachment to polymer, and PDL can promote THETCs attachment to polymer, and suggest that PLGA 85/15 coated with PDL may be used as a new type attachment substrate for THETCs.

Cell Adhesion↗
PubMed1999

[The present research situation of cause of formation of impedance cardiograph waveform].

This paper summarized the present research situation of cause of formation of impedance cardiograph waveform in two aspects of early and current research on it by the means of consulting a great deal of domestic and foreign data. The paper pointed out that a practicable way for correcting Kubicek theory and its physical model, making SV formula more accurate is to apply finite element technology to the research field under the guide of impedance cardiograph electric field theory. At the same time, the paper made preliminary introduction on the author's research work in the area.

Animals↗
PubMed1999

[Purification and properties of glutamate dehydrogenase from Pseudomonas pseudoalcaligenes].

Glutamate dehydrogenase was purified from the crude extract of Pseudomonas pseudoal-caligenes. The enzyme had a molecular weight of 290,000 and was composed of six subunits with identical molecular weight of 47,000. The enzyme was highly specific for NADP(H) and the substrates. The biochemical properties such as kinetic parameters and heat stability were also examined. The purified GDH showed considerable loss of activity upon freezing.

Glutamate Dehydrogenase↗
PubMed1999

[Scavenging effects of Astragalus and Gynostemma pentaphyllum with its product on O2-. and .OH].

The scavenging effects of Astragalus and Gynostemma pentaphyllum with its products on O2-. (produced by the autoxidation of pyrogallol) and .OH (generated from the Fenton reaction) were investigated by electrochemical method. The results showed that they could scavenge the active oxygen free radicals effectively, however, their scavenge ability was different for O2-. and .OH. The inhibitory effect of Ginsenoside Rb1 and Astragaloside IV on O2-. and .OH was the most strongest. Their IC50 values were calculated respectively. The scavenging ability of Astragalus samples on O2-. was in the order of the following: astragaloside IV > crude radix astragali > mongolia radix astragali > hebei radix astragali > radix astragali > radix astragali mixfry with honey; and the scavenging effect on .OH was: astragaloside IV > hebei radix astragali > radix astragali mix-fry with honey > radix astragali > crude radix astragali > mongolia radix astragali. The scavenging activity of gynostemma samples on O2-. was: ginsenoside Rb1 > gynostemma jujube tea > tabellae Jiaogulanosidi > anguo market gynostemma > hebei qingxian gynostemma; while on .OH, the inhibitory ability was: ginsenoside Rb1 > gynostemma jujube tea > anguo market gynostemma > hebei qingxian gynostemma > tabellae Jiaogulanosidi.

Astragalus Plant↗
PubMed1999

The study of influencing factors on the growth characters of Sprague-Dawley rat retinal neurons in vitro.

PURPOSE: To investigate the influencing factors in culturing Sprague-Dawley (S-D) rats retinal neurons in order to lay foundation for further experimental research. MATERIALS AND METHODS: Retinal cells were plated on plastic plates and coverslips coated with poly-l-lysine or ethylene imine polymer for primary culture. The cultured cells were divided into following groups: 1. Culture medium changed every 2 to 3 days vs changed only once; 2. Cytosine arabinoside (Ara-C) added to the culture medium vs not added. The cells were observed and pictured under inverted phase contrast microscope. The cells were identified through immunocytochemistry. RESULTS: The immunofluorescence showed that most of the cultured cells were neurons, among them were a few retinal ganglion cells. In the cultured group of which substrata coated with poly-l-lysine and culture medium added with Ara-c, the neurons intended to aggregate into clusters with relatively straight neurites. In the group of which substrata coated with ethylene imine polymer and medium added with Ara-c, the neurons grew dispersively with bent neurites. Both of them survived for 2 to 3 weeks. The cells which plated in the medium not added with Ara-c did not aggregate into clusters and survived longer than 4 weeks. In the group of which medium changed several times, the survival time of neurons was shorter than that in the medium changed only once. CONCLUSIONS: The retinal neurons plated on the substrata coated with ethylene imine polymer are easy to observe because of its dispersive growth. It is not favorable for the growth of the neurons by changing culture medium many times. Ara-c may possibly have side effect on the growth of retinal neurons.

Animals↗
PubMed1999

[Dynamic observation of serological and histological changes of Chinese rhesus monkeys infected by hepatitis G virus].

OBJECTIVE: To study the genesis, development and pathogenesis of hepatitis G. METHODS: The Chinese Rhesus monkeys were intravenously injected with the serum from a hepatitis G patient only with HGV RNA positive. The dynamic changes of serum and liver tissues of the animals were observed before and after infection. Also the immunohistochemical study were done with monocolonal antibody against NS5 gene antigen of HGV. One male monkey was dissected and the internal organs were taken for histological examination 18 months after infection. RESULTS: Serum ALT and AST became increasing 30 days after infection and showed abnormal continuously for 9 months. Spotty and focal necrosis and piecemeal necrosis were found in liver tissue from 2 to 18 months after infection. Positive staining of HGV antigen was present in cytoplasm of liver cells by immunohistochemistry. Histological observation showed that the internal organs were normal except the liver tissue in which the damages were similar with that in hepatitis. CONCLUSION: The successful infection of Chinese Rhesus monkey by serum from hepatitis G patient can used as a good animal model for the study of hepatitis G.

Animals↗
PubMed1999

[Floating culture of human nasal glandular cells].

OBJECTIVE: To establish a floating cultural model of human nasal glandular (HNG) cells. METHODS: HNG cells were cultured on floating collagen gels. RESULTS: Cultured HNG cells incubated with monoclonal antibody for cytokeratin stained positively. After two-week culture, the cells stained blue by AB-PAS staining. Transmission electron microscopy showed that the cells exhibited numerous microvilli on their surfaces and had numerous secretary granules. They were well polarized and interconnected by junctional complexes. Cultured HNG cells possessed typical characteristics of normal epithelium. CONCLUSION: The floating cultural model of HNG was successfully established.

Cell Culture Techniques↗