Biomedical subjects

R Gao

Publications and source records attributed to R Gao.

At least 55 records · Page 3Linked to original sources

PubMed2000

[Effect of ginsenosides on proliferation and differentiation of human CD34+ hematopoietic stem/progenitor cells].

OBJECTIVE: To investigate the effect of ginsenosides (GS) on proliferation and differentiation of human CD34+ stem/progenitor cells. METHODS: CD34+ hematopoietic progenitor cells were isolated from umbilical cord blood by using the immune beads sorting system. The cells were exposed to GS of different concentrations in both liquid culture and semi-solid culture, and the elevation rate on proliferation of CD34+ stem/progenitor cells and colony formation were estimated. The cells were marked with monoclonal antibody and the marker was examined by flow cytometry after incubated with GS for 14 days. RESULTS: GS (5-50 micrograms/ml) could raise the colony production rate of BFU-E, CFU-E, CFU-GM, CFU-GEMM by (87.6 +/- 2.6)%, (63.3 +/- 2.8)%, (58.0 +/- 3.1)% and (96.3 +/- 5.5)% respectively (all P < 0.01), and the best effect in improving cell proliferation of CD34+ cells in vitro was obtained when the concentration of GS was 25 micrograms/ml. After incubation with GS for 14 days, number of CD33+ cells was increased by GS in a dose-dependent manner with a peak increasing rate at 200 micrograms/ml. In the presence of GS 50 micrograms/ml, CD15+ cells were reaching the peak. Number of CD71+ and G-A+ cells increased only when the concentration of GS was 25 micrograms/ml. CONCLUSION: GS could not only promote the proliferation but also induce the differentiation of CD34+ hematopoietic stem/progenitor cells, GS may play the role by cooperating with hematopoietic growth factor, and by its growth factor-like function in the regulation of hematopoiesis.

Antigens, CD34↗

PubMed2000

[The relationship between clinical types of postinfarction angina and stenosis of ischemia-related artery].

OBJECTIVE: To approach the pathogenesis of postinfarction angina and set up its treatment guidelines. METHODS: 67 patients with postinfarction angina undergoing coronary angiography during the hospitalization were studied. RESULTS: (1) According to the clinical classification of angina pectoris, spontaneous angina is the most common type (43.9%); mixed angina is second (25.7%), effort angina and variant angina are relatively low frequency (16.7% & 13.6%). (2) Stenosis >or= 90% in the ischemia-related artery accounted for the anginal symptoms constituted 100%, 82.8%, 72.7% and 44.4% of the cases with mixed angina, spontaneous angina, effort angina and variant angina respectively. (3) Postinfarction angina caused by non infarction-related artery was relatively less frequent (8.9%). CONCLUSIONS: Severe residual stenosis of infarction-related artery is the main pathologic factor on the pathogenesis of postinfarction angina, so early interventional therapy or bypass surgery should be taken.

Adult↗

PubMed2000

[Synergistic effect of monocyte chemotactic protein-1 and aristolochic acid I on transdifferentiation of human tubular epithelial cells in vitro].

OBJECTIVE: To test the possible role of monocyte chemotactic protein-1 (MCP-1) and its synergistic effect with aristolochic acid I (AAI) on tubular epithelial-myofibroblast transdifferentiation (TEMT) of human renal tubular epithelial cells (HKC) in vitro. METHODS: The cultured HKC cells were divided into four groups: (1) negative control (serum-free); (2) MCP-1 group; (3) AAI group; (4) AAI + MCP-1 group. The expression of alpha-smooth muscle actin (alpha-SMA), vimentin and cytocreatin was assessed by indirect enzyme immunohistochemistry and the percentages of alpha-SMA((+)) HKC cells were assessed by flow cytometry. RESULTS: The expression of cytocreatin of HKC cells decreased, while the expression of alpha-SMA, vimentin increased when treated with MCP-1 or with AAI and MCP-I concomitantly. Alpha-SMA((+)) HKC cells cultured in serum-free medium was 3.1% by flow cytometry. The percentages of alpha-SMA((+)) HKC cells were 8.6%, 9.6%, 13.4% (P < 0.05 vs control) when treated with 20, 40, 80 microg/L of AAI. The percentages of alpha-SMA((+)) HKC cells were 0.5% and 1.4% (P > 0.05 vs control) when treated with 5, 10 microg/L. The percentages of alpha-SMA((+)) HKC cells were 20%, 26.2%, 20.3%, 23.2% (P < 0.05 vs control) when treated with 0.001, 0.01, 0.05, 0.1 microg/L of MCP-1. When the HKC cells were treated with MCP-1 (0.1 microg/L) and AAI (5, 10, 20, 40 microg/L), the percentage of alpha-SMA((+)) cells increased markedly to 23.2%, 98.7%, 81.5%, 65.1% (P < 0. 01 vs group 1, 2, 3, respectively). CONCLUSIONS: These findings suggest that: (1) MCP-1 may induce the transdifferentiation of HKC cells into myofibroblasts in vitro; (2) AAI at some doses may partially induce HKC cells transdifferentiation. (3) MCP-1 and AAI may have a synergistic effect on transdifferentiation of HKC cells in vitro.

Actins↗

PubMed2000

[Effect of left ventricular diastolic dysfunction on pathogenesis of angina decubitus].

OBJECTIVE: To investigate the effect of left ventricular diastolic dysfunction on the pathogenesis of angina decubitus. METHODS: The study population consisted of three groups: (1) group 1, 31 patients with angina decubitus who had ejection fraction > 50%; (2) group 2, 20 patients with coronary artery disease but without angina decubitus; group 2 and 1 were matched for age, EF and extent of coronary artery disease; (3) group 3, 20 patients without cardiovascular diseases. RESULTS: Left ventriculography (LVG) showed that LV first 1/3 filling fraction (1/3 FF) and LV late 1/3 FF were 0.30 +/- 0.12, 0.41 +/- 0.12, 0.46 +/- 0.07 and 0.36 +/- 0.09, 0.31 +/- 0.08, 0.29 +/- 0.06 in groups 1 to 3 respectively. LV first 1/3 FF was significantly lower in group 1 than in group 2 and 3 (both P < 0.001), but LV late 1/3 FF was much higher in group 1 than in groups 2 and 3 (P < 0.05 and P < 0.01, respectively). Left ventricular end-diastolic pressure (LVEDP) was markedly increased before and after LVG in groups 1 and 2 as compared with group 3 (P < 0.001 and P < 0.05, respectively). The difference of LVEDP caused by left atrial contraction (LACD) was much higher before and after LVG in group 1 than in group 3 (P < 0.01 and P < 0.001, respectively). However, there were significant differences in LVEDP and LACD tested between before and after LVG in group 1 (both P < 0.01). No statistical differences were found in LVEDP and LACD tested between before and after LVG in both group 2 and group 3. CONCLUSION: Patients with angina decubitus have LV diastolic dysfunction, which may be closely related to the pathogenesis of angina decubitus.

Adult↗

PubMed2000

Detection of glutamate and gamma-aminobutyric acid in vitreous of patients with proliferative diabetic retinopathy.

PURPOSE: To study the levels of glutamate and gamma-aminobutyric acid (GABA) in vitreous of patients with proliferative diabetic retinopathy (PDR) and to investigate their roles in retinal ischemia. METHOD: Vitreous samples were collected from 25 patients (27 eyes) with PDR and 14 patients (14 eyes) with idiopathic macular hole. Glutamate and GABA detection were performed by high-performance liquid chromatography (HPLC). RESULTS: Patients with PDR had significantly higher concentrations of glutamate and GABA than the control group. The glutamate level has a significantly positive correlation with GABA level. CONCLUSION: Detection of glutamate and GABA in vitreous provides biochemical support for the mechanism and treatment of ischemic retinal damage in patients with PDR.

Diabetic Retinopathy↗

PubMed2000

Quantitative study of basic fibroblast growth factor in vitreous with proliferative vitreoretinopathy.

OBJECTIVE: To quantitatively study basic fibroblast growth factor (bFGF) in the vitreous of proliferative vitreoretinopathy (PVR) in order to understand the role of bFGF in the development of PVR. METHOD: High sensitive sandwich enzyme immunoassay technique (ELISA) was used to measure bFGF level in vitreous of normal eyes, the eyes of PVR-C or PVR-D grade, eyes of vitreous hemorrhage and the serum levels of bFGF in PVR-D patients. RESULTS: The levels of bFGF in the vitreous were: median 5.20 ng/L, quartile 15.47 ng/L in 20 normal eyes; median 3.12 ng/L, quartile 10.48 ng/L in 35 PVR-C eyes; median 46.56 ng/L, quartile 113.96 ng/L in 26 PVR-D eyes; median 1.40 ng/L, quartile 6.25 ng/L in 25 vitreous hemorrhage eyes. The vitreous bFGF level in PVR-D group was significantly higher than that in the normal group, PVR-C group and vitreous hemorrhage group (P < 0.01). The mean of serum-bFGF level was 18.33 +/- 3.39 ng/L. The vitreous bFGF level of PVR-D group was significantly higher than serum-bFGF level (P < 0.01). And the vitreous-bFGF level in PVR-D group was significantly higher in larger retinal tear subgroup. CONCLUSION: The results suggested that bFGF is involved in the development of PVR.

Adult↗

PubMed2000

The effect of left ventricular diastolic dysfunction on the pathogenesis of angina decubitus.

OBJECTIVE: To investigate the effect of left ventricular diastolic dysfunction on the pathogenesis of angina decubitus (AD). METHODS: The study population consisted of three groups: 20 individuals without cardiovascular studied as group I. Group II included 20 patents with coronary artery disease and without AD. Thirty-one patients with AD and ejection fraction (EF) > 50% were studied as group III. Group II and III were matched for age, EF and extent of coronary artery disease. RESULTS: Left ventriculography (LVG) showed that left ventricular (LV) first 1/3 filling fraction (1/3FF) was significantly lower in group III than in group II and I (both P < 0.001), but LV late 1/3 FF was much higher in group III than in group II and I (P < 0.05, P < 0.01). Left ventricular end-diastolic pressure (LVEDP) was markedly increased before and after LVG in group II and III as compared with group I (both P < 0.05, both P < 0.001). The difference of LVEDP caused by left atrial contraction (left atrial contraction pressure difference, LACPD) before and after LVG was much higher in group III than in group I ( P < 0.01, P < 0.001). However, there we significant differences in LVEDP and in LACPD between before and after LVG only in group III (both P < 0.01). CONCLUSION: The patients with AD have LV diastolic dysfunction, which may be closely related to the pathogenesis of angina decubitus.

Adult↗

PubMed1999

Purification, properties, and amino acid sequence of a hemoglobinuria-inducing phospholipase A(2), MiPLA-1, from Micropechis ikaheka venom.

Dark-colored urine is one of the clinical symptoms of envenomation by Micropechis ikaheka (New Guinea small-eyed snake). We have purified a phospholipase A(2), MiPLA-1, which induces dark-colored urine in experimental mice, to homogeneity. The analysis of the dark-colored urine by electrophoresis and N-terminal sequence determination indicated that the color of mouse urine is due to hemoglobin in the urine but not myoglobin. MiPLA-1 is the first hemoglobinuria-inducing toxin. Insignificant hemolytic activity of MiPLA-1 indicates that hemoglobinuria is not due to lysis of erythrocytes by MiPLA-1. This suggests that hemoglobinuria induced by MiPLA-1 may be due to kidney leakage caused by unknown mechanisms. MiPLA-1 also showed other biological effects, including myotoxicity as well as anticoagulant and antiplatelet effects. Structural studies show that MiPLA-1 is a basic protein with a molecular mass of 14041.60 +/- 1.78 as determined by electrospray mass spectrometry. We have determined the complete amino acid sequence of MiPLA-1. It is a 124-amino-acid protein with a "pancreatic loop" and belongs to group IB phospholipase A(2) enzymes. Two short segments flanked by proline brackets are found in the sequence of MiPLA-1. These segments are on the surface of the molecule and hence may be involved in protein-protein recognition.

Amino Acid Sequence↗

PubMed1999

[The intracellular signaling pathway initiated by ginsenosides in hematopoietic cells].

OBJECTIVE: To investigate that ginsenosides (GS) promotes proliferation of hematopoietic cells by virtue of the intracellular signaling pathway. METHODS: Three human megakaryocytic cell lines and Northern blot analysis, electrophoretic mobility shift assay (EMSA), antibody gel supershift assay and UV-radiation cross-linking were used. RESULTS: After treatment with GS, GATA-2 mRNA levels in CHRH-288, Meg-01 and MO7e cells were increased by 1.84-, 2.43- and 1.52-fold, respectively, while GATA-1 mRNA levels remained as low as pretreatment. GATA binding activities were elevated in all the three GS treated cell lines. The GATA binding complex appeared as a band with an approximate molecular weight of 50,000 corresponding to the size of GATA-2 protein. CONCLUSIONS: The intracellular signaling pathway initiated by GS was involved in transcription factor GATA-2. GATA-2 might play the key role in the GS induced upregulation of megakaryopoiesis.

Cell Line↗

PubMed1999

[Potentiated effects of total saponins of Panax Ginseng on inhibition of leukemic cells by cytotoxic drugs].

OBJECTIVE: To investigate the potentiated effects of total saponins of Panax Ginseng (TSPG) on inhibition of leukemic progenitor cells by cytotoxic drugs in acute myelocytic leukemia. METHODS: Using bone marrow culture of colony forming unite-acute myeloid leukemia (CFU-AML) method, the sensitivity of leukemic cells obtained from 18 patients to homoharringtonin (HHr), cytarabine (Ara), adriamycin (Adr) and etoposide (VP-16) were detected separately. RESULTS: TSPG alone (20 micrograms/ml) could stimulate proliferation of CFU-AML obviously, and increase the colony numbers by 37.98% over the non-TSPG control (P < 0.01). In the presence of TSPG, the inhibition rates of CFU-AML of HHr, Ara, Adr and VP-16 were 51.2%-62.0% respectively, which were significantly higher than 30.4%-47.4% of non-TSPG control (all P < 0.01). In the combination of TSPG with cytotoxic drugs, the leukemic progenitor cells became more sensitive to cytotoxic drugs, CFU-AML colony numbers at 1.84-2.23 fold as more as those of non-TSPG control were inhibited by HHr, Ara, Adr and VP-16. Sensitivity test of 17 among 72 drugs reversed from resistant (suppression rate less than 30%) to sensitive (suppression rate more than 30%) by TSPG. CONCLUSIONS: TSPG could drive non-cycling leukemic progenitors to enter cell cycle, and thereby enhance their susceptibility to cytotoxic drugs.

Adult↗

PubMed1999

[The clinical features of myocardial infarction in patients younger than 35 years and over 45 years of age].

OBJECTIVE: To investigate the clinical features and the characteristics of coronary angiography in young patients with myocardial infarction. METHODS: 27 patients younger than 35 years with myocardial infarction were studied with respect to their history, habit of smoking and drinking and body weight index. Comparison was made between the left ventricular ejection fraction with ultrasound method and X-ray heart/chest ratio in patients with or without thrombolytic therapy. Selective coronary angiography was performed in 23 of the 27 patients. RESULTS: All of the 27 patients were male. 81.5% of them had smoking index more than 100, 55.5% drinking index more than 150, 51.9% family history of hypertension and 72.2% low blood level of HDL cholesterol. Most of the cardiac accidents took place in the night and morning. 17.4% of the patients had angiographically normal coronary arteries and 30.0% mild stenosis (no significant stenosis). 39.1%, 8.7% and 4.4% of the patients had one-vessel, two-vessel and three- vessel disease respectively. The frequency of patients with left ventricular ejection fraction less than 0.5 was 6.0% in patients with thrombolytic therapy and 33.3% without. CONCLUSION: 47.8% of the patients younger than 35 years with myocardial infarction has no or no significant stenosis of the coronary arteries. Heavy smoking is the most important one of relative factors for young patients with myocardial infarction. Other factors include low blood level of HDL cholesterol, drinking index of more than 150 and family history of hypertension in order. Thrombolysis treatment helps to maintain ventricular performance.

Adult↗

PubMed1999

[The association between plasma homocysteine and the number of coronary artery with stenosis].

OBJECTIVE: Previous studies have shown that elevated plasma homocysteine is a risk factor for arterosclerotic disease and is associated with increased severity of carotid-artery stenosis and peripheral arterial disease. In this study, we examine the precise relation of homocysteine to the number of coronary artery with stenosis. METHODS: One hundred and seventeen subjects who underwent coronary angiography from June to October 1998 in our hospital were recruited in this study. Cases (n = 101) with >or= 50% stenosis in at least one of the three coronary vessels were angiographically defined as having coronary heart disease (CHD). While subjects (n = 16) had 0% stenosis in all the three coronary vessels were considered as controls. CHD cases were divided into single-vessel (n = 29), double-vessel (n = 35) and triple-vessel group (n = 37). Plasma homocysteine was measured within 1 week before angiography in all subjects. RESULTS: Mean plasma homocysteine level was significantly higher in coronary patients than in controls [(17.56 +/- 1.14) micromol/L versus (10.59 +/- 0.43) micromol/L, P = 0.02]. Homocysteine level in the triple-vessel group or double-vessel group was significantly higher compared with that in the controls [(19.49 +/- 1.98) micromol/L versus (10.59 +/- 0.43) micromol/L, P = 0.006 and (17.41 +/- 2.03) micromol/L versus (10.59 +/- 0.43) micromol/L, P = 0.036, respectively]. The level of homocysteine in the stingle-vessel group tended to be slightly higher as compared with that in the controls [(15.2 +/- 61.18) micromol/L versus (10.59 +/- 0.43) micromol/L, P = 0.16]. CONCLUSION: Homocysteine level is elevated in patients with coronary heart disease. Higher level of homocysteine is associated with increased number of coronary arteries with stenosis.

Coronary Disease↗

PubMed1999

[The study of ultrastructure of retinal pigment epithelium of transplantation].

OBJECTIVE: To investigate the ultrastructure of retinal pigment epithelium (RPE) for the base of clinical application. METHODS: Pigmented rabbit RPE was transplanted to the subretinal space of 10 unpigmented rabbits by internal route. The ultrastructure of transplanted RPE cells were observed by electron microscopy. RESULTS: The transplantation of RPE was successful. It was shown that the transplanted cells had polarity and attached to Bruch's membrane to form basal infoldings, and the relationships between transplanted cells and the host photoreceptors were also seen. CONCLUSIONS: The internal approach is a practical and useful method for transplantation of RPE. The transplanted RPE can vitalize, perform metabolism and form some normal ultrastructure.

Animals↗

PubMed1999

[Surgical treatment of traumatic retinal detachment with incarceration].

OBJECTIVE: To investigate the method and effect of vitreoretinal surgery for the traumatic retinal detachment with retinal incarceration. METHODS: 13 eyes of traumatic retinal detachment with incarceration were treated by vitrectomy, membrane peeling, relaxed retinotomy, endophotocoagulation, intraocular tamponade, and in some cases scleral buckling procedure. RESULTS: The retinae were attached in all the cases after operation. During the follow-up period of three months to three years, ten eyes kept the retina attached and three cases suffered from recurrent retinal detachment. One of them had had a second surgical procedure and obtained retinal re-attachment. The anatomic result was 11/13. The visual acuities were improved in all the patients. CONCLUSIONS: Traumatic retinal detachment with incarceration is often accompanied with severe proliferative vitreoretinopathy. Combination of vitreoretinal surgery is an effective method for the lesion. Relaxed retinotomy for the incarceration is the key procedure to obtain the operative success.

Adolescent↗

PubMed1999

[Effects of humic acid on lipid peroxidation in arsenosis prevalent areas].

OBJECTIVE: To explore the causes of blackfoot disease in Taiwan. METHODS: Experiments to induce lipid peroxidation by arsenic and humic acid were made in vitro. Arsenic was determined for the water sampled from the arsenosis prevalent areas in Inner Mongolia and blackfoot disease prevalent areas in Taiwan and humic acid determined for the extracts of the coal rich in arsenic sampled from Guizhou Province in China by MDA-TBA colorimetry. RESULTS: Experiments found that humic acid could induce lipid peroxidation caused by sodium salt of unsaturated fatty acids in vitro in a weak and unstable manner, which could be promoted by 0.05 mmol/L of Fe(+ +) and not by 1 mmol/L As(2)O(3). The extent of lipid peroxidation caused depended on the sources, constituents and structure of humic acid samples, those from Inner Mongolia ranked the highest, those from Guizhou and Taiwan the medium and the commercial humic acid (Aldrich Co. in the US) the lowest. The experiments also found that lipid peroxidation caused by commercial humic acid presented a dynamic process in the existence of trace amount of iron, and humic acid could decompose the products of lipid peroxidation. CONCLUSION: The experiments suggested the relations of humic acid and arsenic to iron and other transition elements in the blackfoot disease prevalent areas and areas with an environment rich in arsenic and humic acid.

Arsenic Poisoning↗

PubMed1999

[The measurement of QT dispersion using wavelet transformation].

This paper addressed the application of wavelet to the measurement of QT dispersion and presented a new method using multi-thresholds to determinate the end point of T-wave. The results geined by computer and human were compared. We also suggested that QT dispersion be defined as the SD of 12 QT intervals.

Algorithms↗

PubMed1999

Elevated vascular endothelial growth factor levels in the vitreous of patients with proliferative diabetic retinopathy.

OBJECTIVE: To detect the levels of vascular endothelial growth factor (VEGF) in the vitreous of patients with proliferative diabetic retinopathy (PDR) and to investigate the possible role of VEGF in the development of neovascularization in PDR. METHODS: Undiluted vitreous samples and fasting venous blood samples were obtained from 27 patients with PDR and 14 subjects with idiopathic macular hole who underwent pars plana vitrectomy. The concentration of VEGF was determined by quantitative enzyme-linked immunosorbent assay (ELISA). RESULTS: The level of vitreous VEGF in patients with PDR (median 0.41 ng/ml, range 0.09-11.56 ng/ml) was significantly elevated when compared with that in control subjects (median 0.017 ng/ml, range 0.008-0.04 ng/ml) (P < 0.001). The median of PDR patients' serum VEGF concentration was 0.19 ng/ml (0.090.46 ng/ml) which was far lower than vitreous VEGF concentration (P < 0.05). Vitreous VEGF concentration was higher in PDR patients with retinal detachment than that in patient without retinal detachment (P < 0.05). CONCLUSIONS: Vitreous levels of VEGF were remarkably elevated in eyes with PDR, and they were not influenced by its serum concentrations. VEGF played an important role in neovascularization of PDR.

Adult↗

PubMed1998

Effects of random perturbations in plastic optical fibers

REVIEW The most important feature of an optical fiber waveguide is its bandwidth, which defines its information-carrying capacity. A major limitation on the bandwidth of multimode glass and plastic optical fibers is modal dispersion, in which different optical modes propagate at different velocities and the dispersion grows linearly with length. However, in plastic optical fibers, experimental and theoretical results indicate that the modes are not independent but are highly coupled, which leads to a characteristic square-root length dependence and an unanticipated large enhancement of the bandwidth to gigahertz levels. The ever increasing demands for low-cost, high-bandwidth communications media for voice, video, and data transmission in short- and medium-distance applications are generating a new assessment of multimode optical fibers to serve as high-speed fiber links.

Journal Article↗