Biomedical subjects

G Yang

Publications and source records attributed to G Yang.

At least 163 records · Page 9Linked to original sources

PubMed2000

Acute vaginal candidosis model in the immunocompromized rat to evaluate delivery systems for antimycotics.

A rat model of vaginal candidosis, suitable for screening new antifungal compounds or novel formulations was developed and validated. Two strains of Candida albicans, different inoculation schedules, quantitative assays for fungal burden and the necessity for immunosuppression were tested. The infection was evaluated clinically and histologically by fungal counts from the vaginal discharge. The animals without immunosuppression did not sustain the infection beyond 2-3 days, however, after immunosuppression with cyclophosphamide, the infection can be maintained for about 2 weeks and is suitable for the testing of topical antifungal therapies.

Acute Disease↗

PubMed2000

[Experiment study of auto-cartilage engineering].

OBJECTIVE: To engineer diversified shapes of neocartilage from auto-cartilage and provide a new method to reconstruct cartilage. METHODS: Cartilage obtained from the ear of 5-week-old New Zealand rabbits was cut into pieces of 0.5 mm x 0.5 mm, which were seeded onto the three-dimensional polylactic acid foams. The cartilage-polymer construct was implanted into a subcutaneous pocket of the donor rabbit. Animals were sacrificed at 3rd, 6th month after implantation. The retrieved implants in each animal were used for gross measurement and histological analysis. RESULTS: Gross examinations of the specimens at 6 months after implantation revealed that there was neocartilage formation; the maxim size was 8 mm x 8 mm. The cartilage showed no signs of resorption. Histological evaluation confirmed the generation of cartilage. The polymer substrate support cell proliferation. The extracellular matrix stained strongly positive for S-GAGs with Alcian blue staining. CONCLUSION: Neocartilage can be created using free auto-cartilage transplantation on appropriate polymer templates.

Animals↗

PubMed2000

[Ecotourism exploitation model in Bita Lake Natural Reserve of Yunnan].

Bita lake provincial natural reserve is located in Shangri-La region of North-western Yunnan, and was set as a demonstrating area for ecotourism exploitation in 1998. After a year's exploitation construction and half a year's operation as a branch of the 99' Kunming International Horticulture Exposition to accept tourists, it was proved that the ecotourism demonstrating area attained four integrated functions of ecotourism, i.e., tourism, protection, poverty clearing and environment education. Five exploitation and management models including function zoned exploitation model, featured tourism communication model signs system designing model, local Tibetan family reception model and environmental monitoring model, were also successful, which were demonstrated and spreaded to the whole province. Bita lake provincial natural reserve could be a good sample for the ecotourism exploitation natural reserves of the whole country.

China↗

PubMed2000

A study of Hodgkin/Reed-Sternberg cells using single cell polymerase chain reaction.

OBJECTIVE: To investigate the characteristics of Hodgkin/Reed-Stemberg (H/R-S) cells found in patients with various types of Hodgkin's disease (HD). METHODS: H/R-S cells were micropicked from frozen sections of tissues affected by HD. The DNA from these cells was amplified by polymerase chain reaction (PCR) using immunoglobulin heavy chain gene FR III a/JH primers and light chain gene family-specific primers. RESULTS: A total of 52/135 (35.8%) isolated cells showed the specific products in the reactions. IgH and V kappa 4 rearrangements were repeatedly found in many cells from a lymphocyte predominance type sample; repeated V kappa 4 and individual IgH/V kappa 2,4 rearrangements and individual IgH, V lambda 3/ V kappa 4 rearrangements were found in two different cases of the nodular sclerosis type; repeated IgH/ V lambda 3 and individual V lambda 2,4 rearrangements, repeated V kappa 2,4 rearrangements, repeated V kappa 4 and individual IgH/ V kappa 3 rearrangements, repeated IgH and individual V kappa 3/ V lambda 4 rearrangements were detected in 3 cases of the mixed cellularity type. Repeated and individual IgH rearrangements were found in other 2 cases. CONCLUSION: The H/R-S cells isolated from the lymphocyte predominance subtypes of HD have IgH and V lambda 4 gene rearrangements. This suggests that the lymphocyte predominance type is a proliferation of neoplastic B cells. The cells isolated from the mixed cellularity and nodular sclerosis types derive from B lineage cells at various stages of differentiation because of the presence of their IgH, kappa and/or lambda gene rearrangements. To our knowledge, this is the first time that the lambda gene rearrangement was detected in H/R-S cells.

Gene Rearrangement↗

PubMed2000

Increased expression of intercellular adhesion molecule-1 in mouse focal cerebral ischemia model.

OBJECTIVE: To quantitatively measure the temporal profiles of intercellular adhesion molecule-1 (ICAM-1) protein in mouse brain after middle cerebral artery occlusion (MCAO). METHODS: Adult male CD-1 mice received 0, 3, 6, 12, 24, 48 and 72 hour(s) of permanent MCAO with an intraluminal suture technique. The degree and the extent of occlusion were determined using a laser Doppler flowmeter. ICAM-1 positive expression in ischemic regions was determined immunohistochemically and ICAM-1 protein was quantitatively measured using immunoprecipitation and Western blot analysis. RESULTS: After MCAO, surface cerebral blood flow (CBF) in the ischemic hemisphere decreased to 9%-15% of the baseline in each time point of 7 to 8 animals. There were no significant differences in CBF measurement during occlusion between groups. Immunohistochemistry showed that ICAM-1 positive microvascular endothelial cells were observed both in the ischemic core and in the perifocal region. There was a tendency for increasing expression of ICAM-1 positive microvascular endothelial cells from the ischemic core to the ischemic margin. Western blot analysis showed that ICAM-1 expression in the ischemic hemisphere began to increase 3 h after MCAO, peaked at 6 h to 12 h, and persisted to 72 h. CONCLUSIONS: ICAM-1 expression increases in mice with permanent MCAO because ICAM-1 can mediate leukocyte-endothelial adhesion and progression of leukocyte infiltration after permanent focal cerebral ischemia. ICAM-1 is one of the important factors participating in ischemic cerebral damage and pathogenesis of stroke.

Animals↗

PubMed2000

Temporary and permanent focal cerebral ischemia in the mouse: assessment of cerebral blood flow, brain damage and blood-brain barrier permeability.

OBJECTIVE: To establish a mouse model of middle cerebral artery occlusion, which mimics focal ischemia in humans and to demonstrate the advantages and disadvantages of the model. METHODS: CD-1 mice (n = 126) had permanent middle cerebral artery occlusion for 24 h, or temporary occlusion for either one hour followed by 23 h of reperfusion or 2 h of occlusion with 22 h of reperfusion. The middle cerebral artery was occluded by insertion of a suture through the internal carotid artery. Reperfusion was established by suture withdrawal. The degree of occlusion and the extent of reperfusion were determined using laser Doppler. Infarct volume was measured with 2, 3, 5-triphenyl tetrazolium chloride staining, and the blood-brain barrier disruption was demonstrated using albumin immunohistochemistry. RESULTS: Blood flow decreased to 14%-19% of baseline in both the permanent and temporary occlusion groups and was restored to 51%-75% of baseline after reperfusion. The infarct volume was smaller in the 1 h/23 h temporary occlusion group (P < 0.05) than in either the 24 h permanent occlusion group or the 2 h/22 h temporary occlusion group. Blood-brain barrier disruption was also smaller in the 1 h/23 h temporary occlusion group than in either the 24 h permanent occlusion or the 2 h/22 h temporary occlusion group (P < 0.05). CONCLUSION: Permanent or temporary middle cerebral artery occlusion causes reproducible brain injury in the mouse. Blood-brain barrier disruption and infarct volume remain important markers of focal cerebral ischemia.

Animals↗

PubMed2000

Oral administration of insulin to female nonobese diabetic mice inhibited diabetes and induced Fas ligand expression on islets of Langerhans.

OBJECTIVE: To detect oral administration of recombinant human insulin to nonobese diabetic (NOD) mice for preventing them from diabetes and insulitis and to detect the effects of oral administration of insulin on Fas and Fas ligand expression on islet of Langerhans. METHODS: Sixty-four female NOD mice were divided into two groups. One group (34) was orally administered recombination human insulin 1 mg in 500 microliters PBS and the other (30) 500 microliters PBS only at age of 5 weeks old, twice a week for the first week, then weekly until 30 weeks of age. RESULTS: Oral administration of insulin to female NOD mice can significantly suppress diabetes and insulitis. The insulitis was less severe in the group fed with insulin than that in the control group (score of insulitis: 1.25 +/- 0.45 vs 3.0 +/- 0.76 at 16 weeks of age, P < 0.01). We examined Fas ligand and Fas expression on islets of Langerhans in both groups of NOD mice by using immunohistochemical techniques. We find that Fas only expressed on islets when the mice suffered the diabetes, whereas Fas ligand expressed on islets of the mice fed with insulin at 16 and 20 week of ages. We did not find Fas ligand positive staining on the islet feeding with PBS. CONCLUSION: We speculated that oral insulin may induce Fas ligand expression on the islets and plays a role in protecting the pancreatic beta-cell from autoimmune destruction. These results show that oral insulin affected autoimmune diabetes and insulitis in NOD mice. The immune mechanism of oral tolerance is closely related to the change of Fas ligand and Fas system.

Administration, Oral↗

PubMed2000

[APC gene expression in precancerous lesions of stomach examined by light and electron microscopic in situ hybridization].

OBJECTIVE: To study the significance of abnormal expression of APC gene in gastric cancer and its precancerous lesions. METHODS: The expression of APC gene was examined in 119 cases of precancerous lesions and 40 cases of gastric cancers by light and electron microscopic in situ hybridization technique. RESULTS: 1. The positive rate of APC gene expression in normal gastric mucosa, mild dysplasia, moderately severe dysplasia, severe dysplasia and gastric cancer was 83.3%, 77.8%, 62.5%, 25.9%, and 6.7%-8.0%, respectively. 2. In 4 types of intestinal metaplasia (IM), APC gene expressed much more frequently in colonic type than in small intestinal type (P < 0.05), more frequently in incomplete type of IM than in complete type (P > 0.05). The positive rate of incomplete colonic type was the highest. 3. Under electron microscope, the APC positive signals were located in the cytoplasm matrix of gastric mucosa cells. They decreased gradually from normal parietal cells, dysplasia cells to cancer cells till negative. CONCLUSION: Abnormal expression of APC gene occurs mainly in precancerous lesion-severe dysplasia. It is considered as an early event during gastric carcinogenesis. Detecting APC gene in gastric mucosa helps predict the trend of dyplasia to become malignant, and diagnose gastric cancer in early stage.

Adenomatous Polyposis Coli Protein↗

PubMed2000

[Attenuation of reperfusion injury in the mouse transfected interleukin-1 receptor antagonist].

OBJECTIVE: To investigate the therapeutic effects of overexpression of interleukin-1 receptor antagonist (IL-1ra), administered by gene transfer, on the transient cerebral ischemic injury in an experimental mice suture model. METHODS: Adenovirus vector encoding human IL-1ra gene (Ad.RSVIL-1ra) or LacZ gene (Ad.RSVLacZ) or normal saline was administered by injection into the right lateral ventricle in adult CD-1 mice. Five days after the virus injection, the mice received 1 h transient middle cerebral artery occlusion with 23 h reperfusion. Surface cerebral blood flow was measured using laser Doppler flowmetry. Brain infarct volume was evaluated on the sections with hematoxylin-eosin staining. Blood-brain barrier (BBB) permeability was determined using immunostaining of extravasated endogenous albumin. The number of intracellular adhesion molecular-1-positive vessels was determined by immunohistochemistry. RESULTS: The infarct volume in the Ad. RSVIL-1ra transfected mice was markedly reduced compared with the Ad. RSVLacZ transfected or saline mice (36.0 +/- 5.3 mm(3) vs 60.0 +/- 6.2 mm(3), 69.5 +/- 6.3 mm(3), P < 0.05). BBB disruption area was also smaller in the Ad. RSVIL-1ra transfected mice than in the Ad. RSVLacZ transfected and saline mice (P < 0.05). The expression of intracellular adhesion molecular-1 (ICAM-1) positive vessels in the ischemic cortex and basal ganglia was greatly attenuated in the Ad. RSVIL-1ra transfected mice (cortex: 135 +/- 23, vs 311 +/- 40 and 357 +/- 51 pound sterling basal ganglia: 90 +/- 21, vs 207 +/- 43 and 259 +/- 43, P < 0.05. CONCLUSION: IL-1ra has neuroprotective property during ischemia/reperfusion injury. Overexpression of IL-1ra via gene transfer can attenuate the expression of ICAM-1 in the ischemic area.

Adenoviridae↗

PubMed2000

[Low-molecular-weight heparin for preventing deep-vein thrombosis after total joint arthroplasty].

OBJECTIVE: To evaluate the efficacy and safety of low-molecular-weight heparin (LMWH) in preventing deep-vein thrombosis (DVT) after total hip and knee replacement (THR, TKR). METHODS: From November 1997 to March 1999, we performed total joint replacement for 47 control patients (34 knees, 28 hips) and for 31 patients (19 knees, 17 hips) who had been given low-molecular-weight heparin for preventing deep-vein thrombosis. All patients received venography of the operated limbs after operation. RESULTS: DVT occurred in 19.4% of the LMWH patients (26.3% in TKR, 11.8% in THR) and the reduction was significant (P < 0.05) compared to the control group (48.4%, 55.9%, 39.3% respectively). The incidence of proximal DVT was also reduced significantly (P < 0.05) from 19.4% of the control group to 2.8% of the LMWH group. CONCLUSION: Low-molecular-weight heparin can significantly reduce the incidence of deep-vein thrombosis after total joint replacement.

Arthroplasty, Replacement, Hip↗

PubMed2000

[Expression of tumor metastasis gene MTA 1 in hepatocellular carcinoma: clinical implications].

OBJECTIVE: To evaluate the relevance of the expression of tumor metastasis gene metastasis-associated 1 (MTA 1) to HCC metastasis. METHODS: A fragment of MTA 1 cDNA was synthesized by reverse transcription (RT)-PCR. A DIG-labeled method of in situ hybridisation (ISH) was used to measure semiquantitatively MTA 1 mRNA in formalin-fixed, paraffin-embedded sections. RESULTS: Most of MTA 1 mRNA positive cells were located on the border of the tumor in some invasive HCC. High MTA 1 expression was found to correlate significantly with portal venous invasion, intrahepatic metastasis, tumor size or distant metastasis (P < 0.05), but not with gender, cirrhosis or AFP level. It also significantly predicted a shorter survival (P < 0.05). CONCLUSION: The overexpression of MTA 1 correlates closely with the invasion process of HCC.

Adult↗

PubMed2000

[Trabeculectomy combined with phacoemulsification for treatment of glaucoma complicated with cataract].

OBJECTIVE: To evaluate the effectiveness of small-incision triple procedure, including phacoemulsification, posterior chamber intraocular lens implantation and trabeculectomy, in patients with coexisting glaucoma and cataract. METHODS: Twenty patients (26 eyes) with coexisting glaucoma and cataract underwent 3.5 mm-incision triple procedure. The mean follow-up was 16.1 months (3 - 41 months). RESULTS: The mean preoperative intraocular pressure (IOP) was (23.01 +/- 2.63) mm Hg (1 mm Hg = 0.133 kPa) which decreased to a mean postoperative IOP of (13.93 +/- 1.85) mm Hg (P < 0. 001). Seventeen (65%) of 26 eyes had a best-corrected visual acuity of >or= 0.6 at the last follow-up (range, 0.05 - 1.0). The mean magnitude of astigmatism was 0.81 D (range, 0 - 3.00 D), 4 eyes had no astigmatism. Although 2 eyes used antiglaucoma medications shortly after the surgery, no eyes used any medications at the last follow-up. The early postoperative complications included corneal edema in 5 eyes (19%) and shallow anterior chamber in 3 eyes (12%). The late complication was mainly the after cataract in 6 eyes (23%). CONCLUSIONS: The small-incision triple procedure appears effective for treating selected patients with coexisting cataract and glaucoma, improving the valid visual acuity rapidly, reducing intraocular pressure with less medications and having less postoperative complications.

Adult↗

PubMed2000

[Geographic information systems spatial analysis on transmission of schistosomiasis in China].

OBJECTIVE: To understand the epidemiologic status and geographical distribution of schistosomiasis in China. METHODS: Relevant detabases were set up after collection of data from two National Sampling Surveys on Schistosomiasis, in 1989 and 1995. Spatial analysis was undertaken after the database linked to the GIS software which was supported by Arc View 3.0a. Correlation analysis was performed to understand the relationship between rates of human infection and cattle infection. RESULTS: The epidemic areas of schistosomiasis with high risk are mainly distributed in the marshland along the Yangtze River and can be identified as five spatial distribution regions based on the results of spatial analysis. Both epidemic areas and positive rates of stool examination in cattle and water buffalo are much wider and higher than that in humans. The positive correlation was seen between infection rate in human and in cattle from data of both sampling surveys. CONCLUSION: The relevant strategy for schistosomiasis control in different spatial regions should be performed accordingly and the measures of control for cattle and water buffalo should be strengthened in the endemic areas.

Adolescent↗

PubMed2000

[Quantitative determination of EAIgG by ABC-ELISA and its clinical significance].

OBJECTIVE: To explore a method for diagnosis of autoimmune hemolytic anemia (AIHA) and evaluate its clinical significance. METHODS: Erythrocyte associated IgG (EAIgG) was quantified in 60 healthy people, 44 patients with warm antibody AIHA (WAIHA), 108 non-immune anemia and 44 other immune diseases (total 256 cases) by using ABC-ELISA were estimated. RESULTS: EAIgG in WAIHA patients were significantly higher than those in other groups (P < 0.01). In the 44 WAIHA patients, 38 were Coombs positive and 6 Coombs negative. EAIgG in Coombs negative was significantly high. The dynamic changes of EAIgG in 12 WAIHA patients were observed during treatment. When patient's condition got better, Hb and RBC increased and EAIgG decreased. CONCLUSION: Quantitative detection of EAIgG is an index in the diagnosis of WAIHA, especially in AIHA with negative Coombs' test. It is also a useful factor for evaluating therapeutic effect and prognosis in WAIHA.

Adolescent↗

PubMed2000

[Determination of vitamin D2 included with beta-cyclodextrin complex in "longmu zhuanggu chongji" by HPLC].

In order to enhance the stability of vitamin D2(VD2), the inclusion complex of VD2 with beta-cyclodextrin(beta-CD) was added in "Longmu Zhuanggu Chongji", a medicine of children for the prevention and cure of rickets. The VD2 in beta-CD-VD2 inclusion complex was satisfactorily determined by both reversed-phase high performance liquid chromatography(HPLC) and ultraviolet spectrometry(UV). The experimental results from UV were in well consistent with those from HPLC. The accuracy and recovery of HPLC measurement were analyzed, and their relative standard deviation(RSD) were given to be 0.63% and 1.54%, indicating the method is quite correct and reliable, and the linear regression equation is reasonable. The "Longmu Zhuanggu Chongji" containing beta-CD-VD2 inclusion complexes was saponified by a mixture of KOH, vitamin C (VC) and alcohol-water(1:2, V/V) at 70 degrees C, then extracted with petroleum ether. An accurate content of the VD2 product was obtained by HPLC. A simple and rapid HPLC method, which can detect VD2 in the inclusion complex and in "Longmu Zhuanggu Chongji", has been established in this work.

Chromatography, High Pressure Liquid↗

PubMed2000

[A histopathologic and immunohistochemical study of 68 cases of hemangioblastoma].

The aim of this study was to evaluate the histologic characteristics of hemangioblastoma (HB) and investigate the histogenesis of its stromal cells. Sixty-eight cases of hemangioblastoma were studied by light microscopy and thirty-three cases were examined by immunohistochemical stainning. Forty-eight of the 68 patients were males and 20 were females. The average age was 37. Fifty-two cases (76.6%) had been present for two months to one year before the diagnosis was made. Sixty cases (88.2%) arose in the cerebellum. Fifty cases (73.5%) appeared as cystic nodules. Histologically, the 68 cases of HB were further categorized into three subtypes: typical (30 cases), cellular (21 cases) and reticular (17 cases). In 33 cases, the stromal cell were positive for NSE, but negative for F-VIII, UEA-1, GFAP and EMA. In summary, there are three essential histologic categories of hemangioblastoma, and its stromal cells may well have the characters of neuroendocrine differentiation.

Adolescent↗

PubMed2000

[Molecular cloning of enhancin gene from Helicoverpa armigera granulosis virus and its expression in E. coli].

In order to provide recombinant enhancin for studying its mechanism of increasing the mortality of larvae infected by HaNPV and creating new insecticide, enhancin gene from Helicoverpa armigera granulosis virus was amplified by PCR technique. 2.7 kb fragment of enhancin gene was cloned into EcoRI/XbaI site of plasmid pBluescript KS. Sequence analysis revealed that enhancin gene was similar with that reported in the literature except eight nucleotides and five amino acids. Thereby enhancin gene was inserted into vector pET-30a and expressed successfully in Escherichia coli BL21(DE3). The preliminary bioassay of expressed product and HaNPV indicated that mortality of larvae increased 31.7%-34.1% in 7 post-infection days and the LT50 decreased at least 1.5-2.1 days.

Amino Acid Sequence↗

PubMed2000

[Studies on chemical constituents of fat oil of Polygala tenuifolia].

OBJECTIVE: To study the chemical constituents of fat oil from root of Polygala tenuifolia Willd. METHOD: The components were separated and identified by gas chromatograpy-mass spectrometry and elucidated on the standard mass spectral data and the percentages were determined by gas chromatographic area normalization method. RESULT: Eighteen constituents were separated and sixteen of them were identified. CONCLUSION: The major components of the fat oil were established first time as oleic acid, linoleic acid, palmitic acid, eicosenoic acid and stearic acid, which make up 87.0%, 7.31%, 3.27%, 1.07%, 0.91% of fat oil respectively.

Fatty Acids↗