Search PubMed⌕ Search

Biomedical subjects

Z Liu

Publications and source records attributed to Z Liu.

At least 289 records · Page 16Linked to original sources
PubMed2001

Antineoplastic mechanism of Octreotide action in human hepatoma.

OBJECTIVES: To investigate whether apoptosis can be induced by Octreotide in human hepatoma cells in vitro and elucidate the antineoplastic mechanism of Octreotide in hepatoma. METHODS: A cultured human hepatoma cell line, BEL-7402, was exposed to Octreotide and apoptosis was evaluated by cytochemical staining (Hochesst 33,258), transmission electron microscopy, agarose gel electrophoresis and flow cytometry (FCM). RESULTS: After exposure to 0.2 microgram/ml Octreotide, apoptosis with nuclear chromatin condensation as well as fragmentation, cell shrinkage and the formation of apoptotic bodies was observed using cytochemical staining and transmission electron microscopy. A DNA ladder in agarose gel electrophoresis was also displayed. FCM showed that the apoptotic cell number rose with an increase in the concentration of Octreotide (0-2 micrograms/ml). There was a positive correlation between Octreotide concentration and apoptotic rate in BEL-7402 cells (r = 0.809, P < 0.05). CONCLUSION: Apoptosis in human hepatoma cells can be induced by Octreotide, which may be related to the mechanism of antineoplastic action of Octreotide in hepatoma.

Antineoplastic Agents, Hormonal↗
PubMed2001

Shifting-sand control in central Tibet.

The middle reaches of the Yarlung Zangbo, the Lhasa, and the Nianchu rivers form the center of politics, economy, and culture in the Tibetan Autonomous Region. Due to the fragility of the natural environment and overexploitation of land by the local people, desertification is becoming a serious problem in the valleys. Shifting sands cover an area of 578 km2 and have caused problems such as damage to farmland and grassland, traffic blockage and burying of water projects. This paper discusses strategies and techniques for combating shifting sands, including reformation of the agricultural structure, exploitation of new sources of energy, and combinations of mechanical and biotic measures. Using mechanical measures, straw barriers, and gravel layer covers, artificial vegetation can be established on the mobile sand dune by sowing and planting introduced species.

Agriculture↗
PubMed2001

[Grey correlation and cluster analysis on relationship between Cercidiphyllum japonicum community and its environment].

The relationship between 10 years old C. japonicum plantation forest community and its environmental conditions was studied by grey correlation method and cluster analysis. The results showed that there existed closer relations among soil organic matter, available Ca, Fe, Mg and N. Except for N and Mn, all soil available elements tested had no direct impact on the absorption and accumulation of corresponding elements by the community. The tree species in different habitats was found to absorb soil elements selectively to some extent. The factors affecting the basal diameter, DBH, height and biomass of C. japonicum could be lined as soil chemical characteristics > soil physical properties > climate factors, in which, available P had little impact on the growth of C. japonicum. It is suggested that C. japonicum could be restored in the area with higher air moisture and with fertile porous soil between elevation of 2200-2700 m.

Cluster Analysis↗
PubMed2001

[Ecological fragility of wetlands in Sanjiang Plain].

This paper presented an index system and a method for evaluating the ecological fragility of wetlands. The indexes were chosen according to the properties and the development pattern of wetland ecosystem in Sanjiang Plain, the values of weighing the relative importance of the indexes were computed by the method of "APH"(The Analytic Hierarchy Process) and the fragility level was evaluated by the method of multi-indexes. A case study showed that the ecological fragility of wetlands in Sanjiang Plain was prominently high. The availability of this method and this index system was also discussed in the paper.

China↗
PubMed2001

[Gap formation features of humid evergreen broad-leaved forest in central subtropical Wawushan Mountain, Sichuan Province, China].

The primary and secondary subtropical evergreen broad-leaved forests at an altitude of 1720-1750 m in Mt. Wawushan National Forest Park, southwestern China investigated to analyze their canopy gap formation characteristics. The sampling method and canopy formation causes were also discussed. In secondary evergreen broad-leaved forest, the gap density was surprisingly only 9 per hm2 and the size of all gaps was, no more than 10 m2. Almost every gap had only one gap maker, and the gap makers often died standing by suppression. Accordingly successful natural regeneration is difficult in small gap, due to the rapidly lateral growth of canopy trees. In primary evergreen broad-leaved forest, the gap density was 15 per hm2, and 56% of the gaps had an area of no more than 40 m2. The largest gap had an area of 256 m2. The canopy gap accounted for 11.1% and expended gap occupied 19.8% of land area in the forest. Median area of canopy gaps and expended gaps was 59 and 105 m2, respectively. Most gaps had more than one gap maker, and gap makers died falling and were often from mortality events separated in time. Most gaps aged over 10 yr and a few were formed recently and the estimated gap formation rate was 0.01 per year. According to falling direction of trees and the relations with growth process, slope aspect and wind, we deduced gap-maker death resulted from integrated influence among topography, climate particular in wind, tree growth characteristics, and interactions of population under competition. Adapting method of plot sampling and projection drawing used in the paper can improve investigation accuracy and help improving comparison of results in different investigation area.

Altitude↗
PubMed2001

[Water distribution and microclimatic effects of sprinkler irrigation on spring wheat field].

Measurements of sprinkler irrigation on spring wheat field indicated that spring wheat canopy could intercept water by 25-30%, and compared with that above canopy in first milking period, the uniformity coefficient below canopy could be increased by 7-9%. Floating and evaporation loss of sprinkler irrigation water could reach 20-25% of the total. In addition, sprinkler irrigation on spring wheat field could decrease air and soil temperature, and increase air actual vapor pressure and relative humidity, which played a definite role in restraining crop transpiration.

Microclimate↗
PubMed2001

[Study on the exercise test in young health men].

OBJECTIVE: To define the reaction of the respiration and circulation; and to find methods to quantitatively evaluation dyspnea and evaluate the methods that determine anaerobic threshold(AT) with the healthy man during exercise. METHODS: Exercise test was used for 43 healthy young man to measure the index of gas metabolism and artery potassium. The relation between the index of Borg scale (BS) and the oxygen uptake per minute (VO2) was observed. The methods of how to obtain anaerobic threshold(AT) were evaluated by the five kinds of gas metabolism. RESULTS: (1) VD/VT were significantly decreased from the rest to the maximal load exercise (0.28 +/- 0.55 vs 0.19 +/- 0.55, P < 0.01). (2) Seran potassium is state of after exercise (3.76 mmol/Lvs +/- 0.29 mmol/Lvs 4.10 mmol/L +/- 0.38 mmol/L, P < 0.01). (3) BS were closely correlated with VO2 during exercise, From the linear regression line 3 variables Borg scale slop(BSS), Threshold load of dyspnea(TLD), and breakpoint load of dyspnea (BLD), could be derived for quantitative evaluation of dyspnea. (4) ATVCO2 were1208 ml/min +/- 233 ml/min, and it were consistent with ATVE and ATVEO2 (P > 0.05). CONCLUSION: The artery potassium is increased after exercise in young health men. The methods of quantrta-tive evaluation of dyspnea can be used during exercise. It is suitable for AT to obtained by the sharp turning point of the carbon dioxide production (VCO2), minute ventilation (VE) and Ventilation equivalent oxygen (VEO2).

Adult↗
PubMed2001

[Correction of polypronuclear zygotes in 31 cases by micromanipulation].

OBJECTIVE: To study the development of polypronuclear zygotes corrected by micromanipulation. METHODS: Thirty one cases of polypronuclear zygotes were corrected during September to December of 1999 through micromanipulation to remove supernumerary pronucleus from polypronuclear zygotes at 37 degrees C and observing their development 24 and 48 hours later to compare with the normal pre-embryos. RESULTS: 17 in 31 (55%) cases of corrected polypronuclear zygotes developed to 2 to 4-cell pre-embryoes 24 hours later. There was significant difference while compare with the normal zygotes. However 48 hours later the cleavage rate of the two group of preembryos was the similar. CONCLUSION: The correction of polypronuclear zygotes by micromanipulation may in some way cause damage to the cleavage ability in part of the zegotes, but the remaining can develope normally.

Cell Division↗
PubMed2001

192Ir endovascular irradiation prevents restenosis after balloon angioplasty in rabbit.

OBJECTIVE: To examine the effect of endovascular irradiation on restenosis after balloon angioplasty in rabbit. METHODS: After the establishment of rabbit iliac atherosclerosis model, balloon angioplasty was performed at the lesion segment of the iliac artery. Rabbits were randomly divided into three groups: control group, 10 Gy irradiated group and 18 Gy irradiated group. Endovascular irradiation was performed for irradiated groups at the dilated sites by introducing the 192Ir radioactive guidewire through a catheter. After four weeks, the animals were killed and the target segments were cut down. Histopathologic and morphometric analyses were carried out. RESULTS: The mean final lumen area in the 18 Gy group was larger than that in the control or 10 Gy group (P < 0.05). The intimal area in the 18 Gy group was smaller (P < 0.05). CONCLUSIONS: 192Ir endovascular irradiation may prevent restenosis after balloon angioplasty. The effect is related to the delivered dose. The mechanism is involved in inhibition of neointimal proliferation.

Angioplasty, Balloon↗
PubMed2001

Eldepryl prevents 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced nigral neuronal apoptosis in mice.

OBJECTIVE: To study the apoptotic effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on the nigral dopaminergic neurons of mice and 1-methyl-4-phenylpyridium ion (MPP+) on pheochromocytoma (PC12) cells, as well as the antagonism of Eldepryl against MPTP's apoptotic effect. METHODS: Three groups of C57BL mice were treated with MPTP, Eldepryl plus MPTP and normal saline, respectively, for 7 days before performing TUNEL (terminal deoxyneucleotidyl transferase-mediated dUTP-x nick end labeling) and FACS (fluorescence activated cell sorting) analyses of neuronal apoptosis in the substantia nigra. The same tests were employed in cell culture to examine apoptosis in PC12 cells treated with MPP+, MPTP or PBS. RESULTS: Intraperitoneal administration of MPTP 30 mg/kg could induce nigral apoptosis, and oral use of Eldepryl prior to MPTP treatment could completely prevent the nigral apoptosis caused by MPTP. MPP+, an intermediate metabolite of MPTP, could lead to the apoptosis of PC12 cells, whereas MPTP itself had no such effect on PC12 cells. CONCLUSIONS: The experiment indicated that the neurotoxin, MPTP, might cause the death of nigral neurons through a mechanism of apoptosis and this effect might be mediated by its bioactive intermediate metabolite MPP+. Eldepryl could protect the neurotoxicity from MPTP.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed2001

Effects of sex hormones on apoptosis in peripheral blood mononuclear cells from patients with systemic lupus erythematosus.

OBJECTIVE: To study the effects of dehydroepiandrosterone (DHEA) and/or estradiol (E2) on apoptosis in peripheral blood mononuclear cells (PBMCs) from patients with systemic lupus erythematosus (SLE). METHODS: The percentage of apoptosis of PBMCs from SLE patients and healthy blood donors were examined by means of AO staining 48 h after culture with DHEA and/or E2 at physiologic or pathologic concentrations. RESULTS: The percentage apoptosis of PBMCs from SLE patients is higher than that of healthy blood donors (P < 0.01). E2, whether at physiological or at pathological concentrations, had no effects no apoptosis of PBMCs from both SLE patients and healthy donors (P > 0.05). Both DHEA and DHEA plus E2 at physiologic concentrations, had no effect on apoptosis of PBMCs from healthy donors (P > 0.05), but significantly inhibited that of SLE patients (P < 0.05); at pathologic concentrations, they promoted apoptosis of PBMCs from SLE patients as well as healthy blood donors (P < 0.05). There were no significant differences between the effects of DHEA and that of DHEA plus E2 (P > 0.05). CONCLUSION: DHEA plays an important role in the apoptosis of PBMCs from SLE patients; low serum levels of DHEA may cause accelerated apoptosis.

Adult↗
PubMed2001

Identification and function of glucose transporter 1 in human mesangial cells.

OBJECTIVE: To evaluate the role of glucose transporter 1 (GLUT1) in the glucose uptake of glomerular mesangial cells. METHODS: Cultured human glomerular mesangial cells were used. The expressions of glucose transporter 1 mRNA and protein were detected with reverse transcription-polymerase chain reaction (RT-PCR), flow cytometry and immunofluorescence staining. Glucose uptake was determined with 2-deoxy-[3H]-D-glucose uptake assay. RESULTS: The expressions of GLUT1 mRNA and proteins were detected in human mesangial cells. Glucose uptake and its kinetics assay showed that GLUT1 is a functional glucose transporter in cultured human mesangial cells, and that its function could be inhibited by the specific inhibitor, Phloretin. CONCLUSION: GLUT1 is the predominant glucose transporter in human mesangial cells, which has the kinetic characteristics of high affinity and low capacity for D-glucose. This suggests that in order for mesangial cells to take up excessive quantities of glucose, as in diabetes, changes in glucose transporter expression, translocation or activity may be required.

Glomerular Mesangium↗
PubMed2001

Monocyte chemoattractant protein-1 expression in renal tissue is associated with monocyte recruitment and tubulo-interstitial lesions in patients with lupus nephritis.

OBJECTIVE: To investigate the pattern of monocyte chemoattractant prolein-1 (MCP-1) distribution in the renal interstitium and evaluate its pathogenic role in tubulo-interstitial lesions in patients with lupus nephritis, the distribution of MCP-1 in renal tissue was observed. METHODS: Eighteen female patients with biopsy-proven lupus nephritis were enrolled in this study. No intensive immunosuppresive therapy was used in these patients during the 3 months prior to renal biopsy. The distribution of MCP-1, infiltration of CD68+ (macrophage/monocyte), CD4+ and CD8+ cells in the tubulo-interstitium of patients with lupus nephritis was detected using immunohistochemical staining with specific antibodies. Renal specimens from patients with minimal change glomerulonephritis were used as controls. RESULTS: MCP-1 protein was widely distributed in the renal tissue of patients with lupus nephritis, mainly located at the baso-lateral surface of tubular epithelial cells (16/18 biopsies), and on the wall of interstitial blood vessels (9/18 biopsies). In contrast, tubular MCP-1 staining was weak and rare in renal tissue from controls (7.4 +/- 6.2% vs 26.7 +/- 22.8%, P < 0.01). Tubulo-interstitial infiltration of CD68+, CD4+ and CD8+ cells was markedly increased in patients with lupus nephritis as compared to controls. The tubular expression of MCP-1 was strongly associated with the amount of CD68+ cell infiltration in the interstitium (r = 0.5420, P < 0.05) and the extent of interstitial fibrosis. There was no correlation between MCP-1 production in tubules and the degree of urinary protein excretion in patients with lupus nephritis (r = 0.0547, P > 0.05). CONCLUSIONS: The expression of MCP-1 in the renal tubules and vascular wall was markedly increased in patients with lupus nephritis. The overproduction of MCP-1 in renal tissue may contribute to monocyte recruitment in the interstitium and thus result in tubulo-interstitial damage in lupus nephritis.

Adult↗
PubMed2001

The clinical and pathological characteristics of Chinese patients with pauci-immune crescent glomerulonephritis.

OBJECTIVE: To investigate the clinical and pathological characteristics of pauci-immune crescent glomerulonephritis (PICGN) in Chinese patients. METHODS: During 13 years (1985-1998), 6400 patients underwent non-transplanting renal biopsy. Twenty-four patients were diagnosed as PICGN. All clinical and laboratory data of these patients were collected from the patients' records and used for detailed analysis. The diagnosis is based on clinicopathologic findings. RESULTS: Of the 24 patients, 16 were females and 8 were males, with median age of 33 years (ranged 10-76 years). Microscopic polyarteritis (MPA) (33.3%) and systemic vasculitis (8.3%) were the secondary diseases. The incidence of PICGN was 0.38% in renal biopsies and 22.9% in crescentic glomerulonephritis. Clinically, most patients (75.0%) showed rapidly progressive nephritis with enlarged kidneys. At onset, gross hematuria was noted in 58.3% of patients, hypertension in 45.8%, nephrotic syndrome in 41.7%, and oliguria in 25.0%. However, systemic symptoms were rare except for anemia. Pathologically, necrosis of glomerular capillaries (62.5%), infiltration of monocytes and neutrophil cells in glomeruli (66.7%), and vasculitis in the interstitium (53.3%) were observed. In addition, glomerulosclerosis was noted in 45.8%, severe tubular atrophy in 83.3% and interstitial fibrosis in 75.0%. Anti-neutrophil cytoplasmic antibodies (ANCAs) were positive in 52.2%. All patients except two received intensively immunosuppressive therapy. Sixteen patients were available for long-term follow up (median 29.8 months, range 8-92 months). Twelve of them had life-sustaining renal function, four had normal serum creatinine (< 124 mumol/L) and only 4 patients were dialysis-dependent. CONCLUSION: PICGN is not rare in China. Early diagnosis and administration of immunosuppressive therapy, particularly in patients with rapidly progressive glomerulonephritis (RPGN), are important for good prognosis.

Adolescent↗
PubMed2001

[Chromosome locus of ATRA-induced gene RA109 and intracellular localization of RA109 protein].

OBJECTIVE: To define chromosome locus of ATRA-induced gene RA109 and intracellular localization of its encoding protein. METHODS: Chromosome locus was defined by radiation hybrid mapping method and protein localization by green fluorescence protein (GFP) as reporter molecule. RESULTS: RA109 gene was mapped to chromosome 5q35 and its protein was localized in cell nucleus. CONCLUSION: RA109 gene is mapped by radiation hybrid technique to a chromosome region that is rich in disease-related genes. The RA 109-encoding protein is a nucleoprotein.

Chromosome Mapping↗
PubMed2001

[Experience and evaluation of extended resection and lymph nodes dissection in stage T3-4N2M0 lung cancer].

OBJECTIVE: To report our experience of surgical treatment for stage T3-4N2M0 lung cancer. METHODS: One hundred thirty one patients with lung cancer in stage T3-4N2M0 were surgically treated by extended tumor resection, lymph nodes dissection and resection of ipsilateral mediastinal pleura and fatty tissue. RESULTS: The 3-year survival rate of patients in stage T3N2M0 with squamous-cell carcinoma and adenocarcinoma was 34% and 18%, respectively. That for stage T4N2M0 patients was only 13% and 5%, respectively. The survival rate was not improved in patients who received combination treatment in addition to surgery. CONCLUSION: The indication of extended resection with lymph node dissection in the treatment of T3-4N2M0 lung cancer is limited.

Adenocarcinoma↗