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Biomedical subjects

G Yang

Publications and source records attributed to G Yang.

At least 271 records · Page 15Linked to original sources
PubMed1998

[Study on mechanisms of T lymphocyte function changes in mice under simulated weightlessness in terms of IL-2 and Bcl-2 gene transcription].

To understand the mechanisms of T lymphocyte function changes under simulated weightlessness T lymphocyte proliferation (MTT assay), IL-2 production (biological assay), IL-2 gene (dot blot) and Bcl-2 oncogene (RT-PCR) transcription of splenic cell were observed in mice. The results showed that on the 7 th and 14 th day of simulated weightlessness T lymphocyte proliferation and IL-2 production decreased and significant on the 14 th day; on the 7 th and 14 th day of simulated weightlessness IL-2 and Bcl-2 gene transcription decreased, significant on the 14 day. It demonstrated that simulated weightlessness inhibits IL-2 production by decreasing IL-2 gene transcrition. IL-2 and Bcl-2 gene may be regulators of lymphocyte function under simulated weightlessness.

Animals↗
PubMed1998

[Effect of tail suspension on mitochondrial Ca2+ and Mg2+ and parameters of electron microscopic morphometry in rats' skeletal muscle].

Changes of mitochondrial Ca2+, mitochondrial Mg2+ and parameters of electron microscopic morphometry in rats' skeletal muscle after 15 or 30 d tail suspension were observed. The results showed that mitochondrial Ca2+ [correction of Ma2+] mitochondrial Mg2+ increased and morphometry of mitochondrial in skeletal muscle showed that volume density (Vv), surface density (Sv), numerical density (Nv) increased. Mean volume (V) decreased. Specific surface increased in soleus muscle, while that parameter remain unchanged in gastrocnemus musles. It suggests that these changes may be denoted to the decrease of muscular contractive function in simulated weightlessness.

Animals↗
PubMed1998

[Repair of articular cartilage defect with a large area: an experimental study].

OBJECTIVE: To compare and evaluate potentialities and biological characteristics of grafts of chondrocytes cultured on fascia, periosteum and articular cartilage in repairing large defects of articular cartilage. METHOD: The large defects of articular cartilage were repaired with grafts of freeze-stored and fresh chondrocytes cultured on fascia, periosteum and articular cartilage, which were evaluated by a number of observation methods. RESULT: The fresh and freeze-stored fascial chondrocytes were superior to free grafts of chondrocytes in potentiality of formation of new cartilaginous tissue, structure and metabolism of newly formed tissue. Relatively good results were also obtained similarly by using fresh autografts of periosteum and cartilage. CONCLUSION: Chondrocytes can be cultured normally on fascia, which can be regarded as an ideal carrier of chondrocytes.

Animals↗
PubMed1998

[Immunohistochemical investigations of congenital pseudarthrosis of the tibia].

OBJECTIVE: To investigate the etiology and pathology of congenital pseudarthrosis. METHOD: Sixty-three specimens were taken from 21 CPT patients. The antibodies, which were used for immunohistochemical studies, were produced against (1) NF-200 or S-100 protein; (2) type I or III collagen; (3) PCNA. The control specimens were taken from neurofibromatosis and traumatic pseudarthrosis. SABC staining was performed. RESULT: Low positive expression of NF-200 (3.2%) and S-100 (4.8%) was noted in the CPT lesion, whereas high expression of NF-200 (85.2%) and S-100 (88.9%) in the lesion of neurofibromatosis. The soft tissues in CPT had a higher ratio of type III to I collagens in comparison with traumatic pseudarthrosis. Positive expression of PCNA (95.2%) was significantly higher in the soft tissues than that (2.5%) in traumatic pseudarthrosis. CONCLUSION: CPT is a disease of non-neuro origin. Its occurrence has no direct relation with neurofibromatosis. CPT has its characteristic pathology in the periosteum rather than in the bone. The pathological fracture or non-union of CPT is caused by fibromatosis, which has a strong activity of cellular proliferation and corrosion. CPT has its pathological property similar to a tumor.

Adolescent↗
PubMed1998

[Phacoemulsification in myopia and negative or low powered posterior chamber intraocular lens implantation].

OBJECTIVE: The study was designed to investigate the technique and clinical experience of phacoemulsification in myopia and negative or low powered posterior chamber intraocular lens implantation (PC-IOL). METHODS: 120 eyes of 102 cases with myopia and cataract were included (axial length >or=28 mm) and hardness of nucleus was of grade 2 in 5 eyes, grade 3 in 84 eyes, grade 4 in 16 eyes and grade 5 in 15 eyes. Tunnel incision was made and in situ nuclear fracture technique by phacoemulsification was used. Energy and time of emulsification: 50% - 60% of energy was set up and emulsification spent 40s to 2 min. 10 s (mean, 1 min. 11.3s) for nuclear sclerosis of grade 2 or 3.65% - 70% of energy was set up and emulsification spent 48s to 1 min. 22s (mean, 68.7s) for cutting the central nucleus and removing the divided nucleus (grade 4 or 5). RESULTS: There were 120 eyes in this group. Eleven to 22 months after operation (mean 14.5 months) the visual acuities of 0.5 or better with and without correction were obtained in 62.6% and 43.4% respectively. The major complications were corneal edema and rupture of posterior capsule. No retinal detachment and cystoid macular edema were found. CONCLUSION: This operation is suitable for myopia with cataract. It is worth to spread due to good visual result, proper correction of ametropia, prevention of retinal detachment, and decrease of operative complications.

Adult↗
PubMed1998

[Effects of homoharringtonine liposomes and homoharringtonine solution on glaucoma filtration surgery in rabbits].

OBJECTIVE: Homoharringtonine (HHT), a Chinese herbal drug, was used in the form of liposome or solution as an adjunct to glaucoma filtration surgery in rabbits to determine its effect in preventing closure of sclerostomy. METHODS: Forty rabbits that underwent a standard posterior-lip sclerectomy in both eyes were divided into 5 post-operative groups. Group 1 received subconjunctival HHT liposomes (0.025%). Group 2 received subconjunctival blank liposomes and served as control. Group 3 and 5 received subconjunctival HHT solution at low (0.025%) and high (0.1%) doses respectively. Group 4 received subconjunctival normal saline and served as control. Intraocular pressure, interval between operation and bleb failure, rate of scleral fistula occlusion and ocular toxicity were determined in each group. RESULTS: Subconjunctival treatment with HHT solution at a high dose transiently prolongs the survival of filtration surgery, but the subconjunctival use with HHT liposomes or HHT solution at a low dose does not significantly prolong the survival of filtration surgery in rabbits. Significant corneal haze and corneal neovascularization resulted from using HHT at a high dose. CONCLUSIONS: The success rate of rabbit filtration surgery can not be markedly increased by the postoperative use of HHT liposomes or its low dose solution. When the high dosage of HHT solution is used, transient elevation of the success rate can be obtained, however the side-effect is also significantly increased.

Animals↗
PubMed1998

[Study of adsorptive voltammetry for adrenaline on carbon paste electrode].

Adrenaline is determined by adsorptive voltammetry using a carbon paste electrode in a base solution of 0.5 mol.L-1 H2SO4. The peak potential of anode is 0.58 V (vs. SCE). There is a good linear relationship between the peak current and the concentration of adrenaline in the range of 5.0 x 10(-9)-1.0 x 10(-4) mol.L-1. The detection limit of the method is 2.5 x 10(-9) mol.L-1. The recovery is 93.75%-103.33%, and the relative standard deviation is 3.1% (n = 12). The adrenaline hydrochloride injection has been determined with good results by this method. The possible reaction mechanism is discussed. The electrode reaction of adrenaline is irreversible process with two electrons and two protons on the carbon paste electrode.

Electrodes↗
PubMed1998

[Field trials on the efficacy of albendazole composite against intestinal nematodiasis].

AIM: To study the anthelmintic effect of albendazole composite (containing 67 mg of albendazole and 83.3 mg base of pyrantel pamoate per tablet). METHODS: A randomized controlled study was carried out to compare the efficacy of a single dose of 3 or 2 tablets of albendazole composite versus a single dose of 400 mg of albendazole or 10 mg base/kg of pyrantel pamoate for treatment of intestinal nematodiasis including 1,864 cases infected with hookworm, 1,568 cases infected with Ascaris, 1,785 cases infected with Tricuris trichiura and 373 children infected with Enterobius vermicularis. RESULTS: In adults, the egg negative conversion rate of a single dose of 3 or 2 tablets of albendazole composite reached 65.0% and 52.7% for hookworm infection (P < 0.01), 100% and 100% for Ascaris infection, and 26.5% and 19.2% for Trichuris infection (P < 0.01), respectively. There were significantly better effect against hookworm with 3 tablets of albendazole composite than that with single albendazole or pyrantel pamoate (65.0% vs. 47.6% and 38.5%, P < 0.01). The effect of 2 tablets of albendazole composite against hookworm was also higher than that of single pyrantel pamoate (P < 0.01) and equal to single albendazole but the anthelmintic effect against Trichuris infection was lower than that of single albendazole (19.2% vs. 26.5%). In 2-6-year-old children, the effect of 1.5 tablets of albendazole composite against Enterobius vermicularis infection showed an egg negative conversion rate of 100% which was higher than that of single pyrantel pamoate (100% vs. 83.0%, P < 0.01). The worm collection data showed that the worm-expelling action of albendazole composite was much more rapid than that of albendazole. There were no adverse effects of albendazole composite on blood picture, liver or renal function and ECG. The side effect of both 3 and 2 tablets of albendazole composite was mild and transcient. CONCLUSION: Albendazole composite exhibits a synergistic effect of both albendazole and pyrantel pamoate.

Adolescent↗
PubMed1998

[Pharmacognostical identification on Chinese drug zhizhuliao].

In this paper, 2 kinds of Zhizhuliao that original plants are Polygonum suffultum Maxim., P. amplexicaule D. Don. var. sinense Forb. et Hemal. are made an initial study on the characteristics, microscopical and physichemical sides. It provides scientific basis for its comprehensive development and ultilization, and to use in clinical.

Chromatography, Thin Layer↗
PubMed1998

[Study of anti-tumor action and influence on immune function of Allium stativum].

Applying mice test on cancer model of S180 and Lewis cancer by using method clystered stomach(oral), observs the Anti-tumor function. Experiments showed that Allium sativum can inhibit tumor growth and Lengthen lift duration of mice, the rate of inhibiting tumor was 74.35% and life lengthening rate were 42.4%, with control grou comparison. There was profund difference between them. Besides, we discoved Allium sativum can raise immune function of mice.

Allium↗
PubMed1998

Elevated expression of caveolin is associated with prostate and breast cancer.

To identify genes associated with prostate cancer progression, we developed a strategy involving the use of differential display-PCR with a panel of genetically matched primary tumor- and metastasis-derived mouse prostate cancer cell lines. We isolated a cDNA fragment with homology to the mouse caveolin-1 gene. Northern blotting with this fragment revealed increased caveolin expression in metastasis-derived cell lines relative to primary tumor-derived cell lines. Western blotting with a polyclonal caveolin antibody confirmed increased caveolin protein in metastasis-derived mouse cell lines and expression in three of four human prostate cancer cell lines. Immunohistochemical analysis of a human prostate cancer cell line demonstrated a prominent granular pattern of caveolin accumulation. Subsequent analysis of mouse and human prostate specimens revealed minimal caveolin expression in normal epithelium with abundant staining of smooth muscle and endothelium. The frequency of caveolin-positive cells was increased in prostate cancer with markedly increased accumulation of caveolin and a granular staining pattern in lymph node metastatic deposits. In human breast cancer specimens, increased caveolin staining was detected in intraductal and infiltrating ductal carcinoma as well as nodal disease. Caveolin therefore appears to be associated with human prostate cancer progression and is also present in primary and metastatic human breast cancer.

Animals↗
PubMed1997

Transforming growth factor beta 1 transduced mouse prostate reconstitutions: I. Induction of neuronal phenotypes.

BACKGROUND: We previously showed that retroviral transduction of transforming growth factor beta 1 (TGF-beta 1) induces focally hyperplastic lesions resembling benign prostatic hyperplasia (BPH) and an increase in the number of ganglion-like cells in the mouse prostate reconstitution (MPR) model in vivo. In the present study we further characterize the neuronal phenotypes induced by TGF-beta 1 retroviral transduction in MPRs. METHODS: Computer-assisted morphometric analysis was used to evaluate neuronal density. Neuronal cell markers, including neurofilament, neuron-specific enolase, tyrosine hydroxylase, choline acetyltransferase, L-met enkaphaline, and serotonin, were detected by immunostaining. RESULTS: A fourfold increase in neuronal density was observed in TGF-beta 1 retrovirus-transduced MPRs. The relative frequencies of neuronal subtypes remained similar, with catecholaminergic and cholinergic neurons presenting as the most abundant. We found no evidence of infection of neurons; therefore, increased neuronal density was likely due to paracrine activities. CONCLUSIONS: Our results suggest that enforced TGF-beta 1 expression leads to growth and/or survival of both catecholaminergic and cholinergic neuronal cells in mouse prostate reconstitutions.

Acetylcholine↗
PubMed1997

Transforming growth factor beta 1 transduced mouse prostate reconstitutions: II. Induction of apoptosis by doxazosin.

BACKGROUND: To study the possible relationship between adrenergic activities and the pathogenesis of benign prostatic hyperplasia (BPH), we tested the effect of doxazosin, an alpha 1-adrenoceptor antagonist, on prostatic growth in vivo using a mouse model for BPH. METHODS: The mouse prostate reconstitution (MPR) model system with retroviral (BabeTGF-beta 1Neo) transduction of transforming growth factor beta 1 (TGF-beta 1) was used to induce focally hyperplastic BPH-like lesions and increase the number of catecholaminergic neurons. The mice were treated with daily intraperitoneal injections of doxazosin (3 mg/kg). RESULTS: Doxazosin caused a significant reduction in the wet weight of BabeTGF-beta 1-infected MPRs. The percent of PCNA-positive epithelial cells was similar in the doxazosin-treated and water only, control groups. There was a significant increase in the number of epithelial cells undergoing programmed cell death, apoptosis, in the doxazosin group (apoptotic index = 4.7 for doxazosin group vs. 3.1 for control group, P < 0.05). The doxazosin-induced apoptosis was more apparent in TGF-beta 1 transduced MPRs than BAG alpha control MPRs, and was not seen in the prostates of the adult male mice into which the MPRs were engrafted. CONCLUSIONS: Our data demonstrate a novel and potentially important biological activity of doxazosin in vivo in this mouse model of BPH.

Adrenergic alpha-Antagonists↗
PubMed1997

Studies on Interaction of Dodecyltrimethylammonium Bromide with Na- and Al-Montmorillonite

The adsorption isotherms and adsorption enthalpies of dodecyltrimethylammonium bromide (DDTMAB) on Na- and Al-montmorillonite were determined in the pH range 2-12. The basal spacings of the clays were also studied by X-ray diffraction. Interactions of DDTMAB with the two montmorillonites predominate mostly through cation exchange in the pH range studied. In the case of Na-montmorillonite, the amount of adsorption increases with pH, but adsorption enthalpy decreases with pH. For Al-montmorillonite, adsorption enthalpy exhibits nonmonotonic variation with pH, although the amount of adsorption increases with pH monotonously. The adsorption enthalpies of DDTMAB on the clays are negative. The adsorbed DDTMAB molecules in clay interlayers present a bilayer arrangement at saturation. Copyright 1997 Academic Press. Copyright 1997Academic Press

Journal Article↗
PubMed1997

Immunohistochemical studies on Waf1p21, p16, pRb and p53 in human esophageal carcinomas and neighboring epithelia from a high-risk area in northern China.

To better understand the roles of p53 and cell cycle-regulating protein alterations in human esophageal carcinogenesis, we investigated immunohistochemically the distribution patterns of Waf1p21, pRb, p16 and p53 in 22 cases of surgically resected esophageal cancer as well as in the neighboring non-cancerous squamous epithelia. Waf1p21 protein was detected in 13 of the 20 cases of well-differentiated squamous-cell carcinoma (SCC), where the Waf1p21-positive cells were located mainly in the interior layers of the cancer nests. Conversely, p53-positive cells were found mostly in the peripheral layers. Cells containing both Waf1p21- and p53-positive immunostaining were not observed in a double-immunostaining experiment. p16 was detected in both the nucleus and cytoplasm in 3 of the 22 cases of SCC. All of these p16-positive cancers showed an absence of pRb immunostaining; this result is consistent with the idea that expression of p16 is regulated negatively by pRb. Eleven of the 22 esophageal SCCs (50%) showed extensive pRb immunostaining cells, and the remaining 11 cases displayed a few pRb-positive cells or an absence of pRb immunostaining. In a majority of the morphologically normal squamous-cell epithelia samples, immunostaining of Waf1p21 and pRb was found in most of the cells in the parabasal layers (proliferation compartment), where PCNA-positive cells also resided. In the pre-cancerous lesions, Waf1p21 and pRb were detected in cells surrounding the top of the lesioned region, p16-positive cells were scattered in the basal cell hyperplastic and dysplastic lesions and p53-positive cells existed in 2 distinct patterns: "scattered" and "focal".

Carcinoma, Squamous Cell↗
PubMed1997

Isolation and cloning of a Drosophila homolog to the mammalian RACK1 gene, implicated in PKC-mediated signalling.

The mammalian RACK1 protein binds activated protein kinase C, acting as an intracellular receptor to anchor the activated PKC to the cytoskeleton. Genes encoding RACK1-like proteins have been isolated from a wide range of eucaryotic organisms; we report the isolation of a Drosophila member of this family. This Drosophila RACK1-like protein shows 76% identity to the mammalian RACK1 proteins, but only about 60% identity to related proteins from plants and fungi. The Drosophila rack1 gene has a dynamic pattern of expression during early embryogenesis with the highest expression in the mesodermal and endodermal lineages.

Amino Acid Sequence↗
PubMed1997

An Algorithm for the Calculation of the Electrical Potential Distribution in a Charged Capillary with General Electrolytes

Knowledge of the electrical potential distribution is an essential basis for analyzing the flow behavior of electrolytes in a charged capillary, such as electroviscous effects. The cylindrical Poisson-Boltzmann equation (PBE) governs the distribution in the capillary. The PBE is a differential equation that is difficult to solve analytically, especially when the capillary is filled with general electrolytes. In this paper we propose a numerical algorithm to obtain the electrical potential distribution in a charged capillary filled with arbitrary electrolytes. First, we introduce a Poisson-Boltzmann integral equation (PBIE) governing the potential distribution and derived from the physical principles for electrostatic fields and thermodynamic systems. Then we solve the PBIE numerically by iteration. In numerical calculation only the discrete potential is used, and the potential differentials of the first and higher orders are not required. This algorithm essentially removes the difficulty caused by very steep variation of the potential near the wall of the capillary and is easily extended to cover the more general case of arbitrary electrolytes. The results of the examples given in the paper show that the algorithm proposed here is correct, effective, accurate (the relative errors are less than 0.01% when normalized surface potential xi </= 8), and easily implemented on a personal computer.

Journal Article↗