Biomedical subjects

S Liu

Publications and source records attributed to S Liu.

At least 343 records · Page 19Linked to original sources

PubMed2000

[Effect of unsymmetrical cutting along both river slopes on rainstorm-runoff process].

A simulation experiment was conducted to compare the effect of cutting and no-cutting at both slopes along a river on the rainstorm run-off in catchment, and a model was constructed. The results showed that the appearance of outflow and peak flow of surface run-off was later on forest slope than on forest-cutting slope. On forest slope, the duration was prolonged, and the peak flow and surface runoff were lower. These effects were more obvious as the slope gradient was bigger. When rain intensity was 1.98 mm.min-1 and rainfall was 108.8 mm, the peak flow and the total runoff on both forested slopes of gradient 15 degrees was 5% and 4% less than that on the cutting slopes, respectively.

Rain↗

PubMed2000

[Soil moisture dynamics in forest land and wasteland of Loess Plateau].

The dynamics of soil moisture stored in a wasteland and in a forest land in the sub-humid climate region of the Loess Plateau was measured with neutron moisture meter for three successive years. Within the depth of 0-320 cm, the increment of soil water in the test 3 years was respectively -165.7 mm, -15.2 mm and -115.2 mm at the upper and lower position on north slopes and the lower position on south slope of the wasteland. Soil water increased by 17.2 mm at the upper position on north slope of the Chinese pine forest land, after > 380 mm water was consumed yearly by tree transpiration. It is suggested that forest land is essentially different from wasteland in soil water income/expense. The necessity of conducting the approaches for gaining available water of forest land was put forward.

Seasons↗

PubMed2000

Magnetic susceptibility of Dy-DTPA-BMA to reperfused myocardial infarction in an excised dog heart model: evidence of viable myocardium.

OBJECTIVE: To assess the effects of Dy-DTPA-BMA (sprodiamide) on ex-vivo MR imaging of reperfused acute myocardial infarction. METHODS: Eighteen dogs were subjected to 2-hour coronary artery occlusion followed by 24-hour reperfusion. Dysprosium-chelate (Dy-DTPA-BMA) was injected into 16 dogs. Twenty minutes before their sacrifice. Two dogs did not receive the contrast medium and were used as controls. Excised hearts were imaged on T2-weighted spin-echo sequence (T2W SE) and T2*-weighted gradient recalled echo sequence (T2*W GRE), then sectioned and double-perfused for planimetric comparison. RESULTS: Dy-DTPA-BMA induced myocardial signal loss was detected on T2W SE and on T2*W GRE images. The signal loss was observed at the subendocardial location of the myocardial wall inducing an apparent enlargement of the left ventricle cavity and a thinning appearance of the anterior myocardial wall. CONCLUSIONS: Myocyte necrosis diminishes the potency of dysprosium to cause MR imaging signal intensity loss in reperfused myocardial infarction. Pre-infarcted myocardium with potentially reversible viability may be responsible for the effect of the contrast medium.

Animals↗

PubMed2000

High frequency loss of heterozygosity in the region of the DBH locus in bladder cancer.

OBJECTIVE: To determine the location of a putative tumor suppressor gene (TSG), and evaluate the frequency loss of heterozygosity (LOH) of the long arm of chromosome 9 (9q) in bladder cancer. METHODS: We analyzed 25 patients with bladder cancer for LOH of 9q using 25 high-density microsatellite markers. RESULTS: Twenty-three samples (92%) showed LOH at least at one locus on 9q. We identified that the commonly deleted region were at 9q12-q21, 9q22, and 9q34. The rate of LOH was 44.0%, 22.7%, 22.7%, 16.0%, 12.0% on DBH, D9S15, D9S1815, D9S1831, D9S176 locus, respectively, and was not significantly related with grades and stages of tumor. CONCLUSION: These data suggest that alteration of a TSG at DBH of 9q may play an important role in the development of bladder cancer.

Chromosomes, Human, Pair 9↗

PubMed2000

[Serum lipoprotein(a) in woman with pregnancy induced hypertension].

OBJECTIVE: To examine lipoprotein(a) level in woman with Pregnancy induced hypertension (PIH) to elucidate the effect of it on the pathogenesis of the disease. METHODS: Serum lipoprotein (a) total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) levels were measured in 20 normal pregnant woman (control group) and 32 pregnant woman with PIH (PIH group). The PIH group was further divided into the following subgroup: mild, moderate, and severe PIH. We used a transmission turbidimetry method to measure serum lipoprotein(a). RESULTS: (1) The serum lipoprotein (a) levels were higher in PIH group than that in control group (228 +/- 187 mg/L vs 106 +/- 93 mg/L). (2) The serum lipoprotein (a) levels were higher in all PIH subgroups than that in control. (3) The serum levels of TC, TG, LDL-C in the PIH group were higher than those in control, while the level of HDL-C in the PIH group was lower than that in control (0.98 +/- 0.16 mmol/L vs 1.09 +/- 0.17 mmol/L). CONCLUSIONS: This study has demonstrated that lipoprotein (a) levels are elevated in pregnant woman with PIH and associated with severity of the disease. It may involved in the pathogenesis of PIH.

Adult↗

PubMed2000

[Changes of selenium concentration and glutathione peroxidase activity in maternal and cord blood in intrahepatic cholestasis of pregnancy].

OBJECTIVE: To investigate the importance of selenium concentration and glutathione peroxidase (GSH-Px) activity in intrahepatic cholestasis of pregnancy (ICP). METHODS: We measured the selenium concentration by a catalytic polorographic method and GSH-Px activity by a 5,5'-dithionbis (2-nitrobenzoic acid) direct method in maternal and cord blood in 30 pregnant women with and without this disease respectively during the last trimester of pregnancy and post partum and in 30 non-pregnant women. RESULTS: Sults (1) The selenium concentration and GSH-Px activity in maternal blood were found to be significantly lower in ICP than in women with normal pregnancies during the last trimester [(0.0389 +/- 0.0090) mg/L, (0.0477 +/- 0.0094) mg/L, P < 0.001] [(59.31 +/- 11.42) U, (68.48 +/- 10.47) U, P < 0.002] and post partum [(0.0463 +/- 0.0092) mg/L, (0.0510 +/- 0.0093) mg/L, P < 0.05] [(68.12 +/- 11.46) U, (72.67 +/- 9.83) U, P < 0.05]. (2) The selenium concentration and GSH-Px activity in cord blood was significantly decreased in ICP than that of normal pregnances [(0.0387 +/- 0.0093) mg/L, (0.0461 +/- 0.0089) mg/L, P < 0.005)] [(57.66 +/- 12.55) U, (67.46 +/- 11.93) U, P < 0.005)] (3) The activity of the selenoenzyme GSH-Px had a significant positive correlation with selenium concentration (P < 0.001). CONCLUSION: The blood selenium deficiency and reduced GSH-Px activity may lead to the formation of free radicals, which could damage the structure and function of hepatocytes and result in ICP.

Adult↗

PubMed2000

Risk factors for development of diabetes mellitus in women with a history of gestational diabetes mellitus.

OBJECTIVE: To determine whether diabetes recurs in their later life when women have a history of gestational diabetes mellitus (GDM) or abnormal glucose tolerance test (impaired glucose tolerance, IGT). METHODS: Three groups of women were investigated at 5-10 years postpartum. GDM group (n = 45) had been diagnosed as having GDM in their previous pregnancy. IGT group (n = 31) had a history of abnormal glucose tolerance test during previous pregnancy. Normal control group (n = 39) was normal previous pregnant population. Their previous obstetric and medical histories were thoroughly reviewed. Fasting plasma glucose (FPG) and oral glucose (75 g) tolerance test (OGTT) were repeated in all women. RESULTS: Diabetes mellitus (DM) was diagnosed in 33.3% of patients in the GDM group, while in 9.7% in the IGT group and in 2.6% in the normal control group. Incidence of recurring DM in later life was significant higher in the GDM group (P = 0.017). When one or more blood glucose values exceeding WHO criteria for diagnosis of diabetes in their previous pregnancy, the incidence of DM in later life was 60% (3/5, including GDM in women having four abnormal OGTT values), 41.7% (5/12) in women having three, 25% (7/28) in women having two and 9.7% (3/31) in women having one. The women with DM, also with a history of GDM and abnormal OGTT in previous pregnancy, tends to have a high pregnant body mass index (BMI > 25 kg/m2). CONCLUSION: The women suffering from GDM during previous pregnancy have a high risk of recurrence DM. Two or more abnormal OGTT values during pregnancy, blood glucose level exceeding the maximal values at 1 and 2 hours after oral glucose loading and high pregnant BMI are concluded to be useful factors in predicting the recurring DM in their later life.

Adult↗

PubMed2000

Effect of selenium on human myocardial glutathione peroxidase gene expression.

OBJECTIVE: To examine the role of selenium (Se) in the expression and activity of selenium-dependent cellular glutathione peroxidase (GPX-1). METHODS: 46 patients with atrial septal defect or ventricular septal defect were separated into two groups, a control group (23 cases) and a Se supplementation group (23 cases). The Se supplementation group received 400 micrograms selenium per day for 7 days before surgery. We used biochemical techniques, atomic absorption, RT-PCR and cDNA sequence testing methods to evaluate and compare the changes during ischemia/reperfussion (I/R) in myocardial melondialdehyde (MDA) level, GPX activity and gene expression level, GPX cDNA nucleotide sequence, selenium and calcium and magnesium concentration. RESULTS: Before ischemia, taking selenium for 7 days did not change the selenium concentration in either plasma or blood cells in either group. The GPX mean activity level in the selenium group was slightly lower than that in the control group, and the MDA level was equal in both. After 30 minutes of reperfusion, the Se level in plasma and blood cells remained constant, while the myocardial Se concentration and GPX gene expression in the Se group increased significantly. The MDA level in the Se group reduced 4.2%, compared to an 8.2% rise in the control group. The mean level of GPX activity in the Se group was slightly lower than that in the control group. Both pre- and post-myocardial reperfusion, the Se group had a higher rate of myocardial GPX gene expression, and the nucleotide sequence was normal. These results indicate that supplementing Se is not likely to enhance myocardial GPX activity, but it could increase the GPX gene expression level, and thereby enhance the Se patients' myocardial antioxidant level during I/R, allowing free radicals to be scavenged as soon as they are generated. CONCLUSION: Se supplementation could increase myocardial selenium content and improve GPX gene expression during I/R, and in this way defend against free radical peroxide damage to the myocardium.

Adolescent↗

PubMed2000

[Changes of selenium concentration in blood and placenta in intrahepatic cholestasis of pregnancy].

OBJECTIVE: To explore the effect of deficiency of blood selenium and placental selenium on the damage of histomorphology of the placentas in ICP. METHODS: We measured the selenium concentration by a catalytic polorographic method in blood and placenta and glutathione peroxidase (GSH-Px) activity by a 5,5'-dithionbis (2-nitrobenzoic acid) direct method in blood in 30 women with ICP (ICP group) and 30 normal pregnant women (control group). Furthermore, the features of the placentas (10 from control group and 10 from ICP group) pathologic changes were observed microscopically. RESULTS: (1) The selenium concentrations in blood (0.0389 +/- 0.0090) mg/L and placenta (0.3770 +/- 0.0964) mg/kg and the activity of GSH-Px (59.31 +/- 11.42) U in ICP group were found to be significantly lower than those in blood (0.0477 +/- 0.0094) mg/L and placenta (0.4554 +/- 0.0626) mg/kg and the activity of GSH-Px (68.48 +/- 10.47) U in control group, respectively (P < 0.002). (2) The activity of GSH-Px had a significant positive correlation with selenium concentration in blood in ICP group (r = 0.05498, P < 0.001) and in control group (r = 0.06234, P < 0.001). There was a positive correlation between blood and placental selenium concentrations in ICP group (r = 0.6473, P < 0.001). On the other hand, there was not correlation in women with normal pregnancies. (3) Placentas obtained from women with ICP had swelling and fibrinoid necrosis of villi, increasing number of syncytial sprouts, thickening of vasculo-syncytial membrane (VSM) and decreasing size of the intervillous space under light microscopy. Placentas from control group did not show the pathologic changes as mentioned above. CONCLUSIONS: As selenium constitutes the active part of GSH-Px, these results suggest that the placental selenium deficiency may lead to reduced placental GSH-Px activity and the antioxidative defence may have been defective which may be associated with the damage of histomorphology of the placentas in ICP.

Adult↗

PubMed2000

[Numerical alteration of chromosome 8 in pleural effusions].

OBJECTIVE: To study the numerical alteration of chromosome 8 and its application for detecting cancer cells in the pleural effusions. METHODS: In situ hybridization with chromosome 8 centromere probe was carried out in 52 patients with pleural effusions. RESULTS: In 31 lung cancer patients examined, hyperdiploid chromosome 8 was found in the effusions. The same hyperdiploid of the chromosome was also noted in 4 cases of effusion from adenocarcinoma of breast, mesothelioma and lymphoma. In 15 pleural effusions which were reportedly negative in previous cytological diagnosis, hyperdiploid chromosome 8 was found in 3 cases, and diploid chromosome 8 in another 12 cases by in situ hybridization. After reexemination of the samples from the 3 patients with hyperdiploid chromosome 8, adenocarcinoma cells were found in 2 cases, and the third one was a patient being treated with radiotherapy. Hyperdiploid chromosome 8 also existed in the pleural effusions from 2 cases suspicious of adenocarcinoma. CONCLUSION: Hyperdiploid chromosome 8 may be a useful marker to ascertain the malignant nature of pleural effusion.

Adult↗

PubMed2000

[Application of pressure volume curve on individual lung-protective ventilation in rabbits with acute lung injury].

OBJECTIVE: To explore the lung-protective effect of ventilation with tidal volume and PEEP determined on pressure-volume curve in oleic acid rabbit models of acute lung injury. METHODS: 24 New Zealand rabbits were randomly divided into 4 groups (V1P1, V1P2, V2P1, V2P2). After inducing lung injury, the P-V curves were measured and drawn. The low and upper inflection point pressure (Pinf and Pdef respectively) were manually determined. Two levels of tidal volume (V1 = 15 ml/kg, V2 reduced for Pplat < Pdef) and two levels of PEEP (P1 = Pinf, P2 = Pinf - 3 cm H2O) were selected. The peak airway pressure (PIP), plateau pressure (Pplat), mean pressure (PAW), static compliance (Cst), heart rate, arterial blood pressure and blood-gas analysis were measured. The lung tissues were pathologically analyzed with light microscope. RESULTS: The oxygenation was not significantly different among 4 groups. The reduced VT significantly raised PaCO2 and lowered pH. Larger VT reduced arterial blood pressure. VT and PEEP synergetically raised airway pressure. Larger PEEP improved Cst, which was counteracted by larger VT. Reduced VT significantly lessened alveolar barotrauma. Larger PEEP lightened alveolar hyaline membrane formation and hemorrhage. CONCLUSION: The ventilation with VT and PEEP determined on P-V curve has significant protective effect on the acutely injured lung.

Animals↗

PubMed2000

[Assessment of treatment regimens in 58 cases with acute pulmonary embolism].

OBJECTIVE: To explore the best regimen of treatment for acute pulmonary embolism(APE), and to evaluate the efficacy and safety of 2-h infusion of recombinant tissue-type plasminogen activator, Alteplase (rt-PA) and urokinase(UK). METHODS: Fifty-eight patients with APE diagnosed by perfusion lung scanning (ECT) or angiography(CPA) were treated with different regimens: i.e. 2-h infusion of rt-PA or UK (2-h group); low doses of UK for 3-7 days (Qd group); anticoagulants alone and thromboectomy. The results were compared. RESULTS: Of the 41 patients treated with thrombolytic therapy 78% showed improvement in lung perfusion scan and clinical presentation without severe adverse effects, the percentage was significantly higher than that of the anticoagulant group(P < 0.001). The rate of improvement was 84% if thrombolytic therapy was given in 2 h. The mortality rate was lower than anticoagulants and thromboectomy group. The success rate of thromboectomy was 40%. CONCLUSIONS: A 2 h regimen of rt-PA or UK showed reliable efficacy and safety for treatment of APE. The indication of thrombolytic therapy can be extended. Mortality and morbidity could be reduced if thrombolytic therapy followed by anticoagulation is applied as early as possible.

Acute Disease↗

PubMed2000

[Mechanism of retinoic acid receptor alpha-mediated growth inhibition of gastric cancer cells by all-trans retinoic acid].

OBJECTIVE: To study the mechanism of retinoic acid receptor alpha(RAR alpha) in mediating growth inhibition of gastric cancer cells by all-trans retinoic acid(ATRA). METHODS: Expression of RAR alpha was detected by Northern blot. After anti-sense RAR alpha or sense RAR alpha had been transfected into gastric cancer cell lines BGC-823 and MKN-45 respectively, the inhibitory effect of ATRA on cell growth in stable clones was analyzed using MTT assay and colony forming assay in soft agar. The transcriptional activation of retinoic acid response element (RARE) was measured by CAT assay. RESULTS: ATRA could induce expression of RAR alpha in BGC-823 cells, but not in MKN-45 cells. In stable clones, ATRA could inhibit growth of MKN-45 cells transfected with RAR alpha gene, but could not inhibit that of BGC-823 cells transfected with antisense RAR alpha. Transient transfection and CAT assay showed higher beta-RAR response element (beta RARE) transcriptional activation induced by ATRA in MKN-45 cells transfected with RAR alpha compared to parental MKN-45 cells, while lower beta RARE transcriptional activation was seen in BGC cells transfected with antisense RAR alpha gene compared to parental BGC-823 cells. CONCLUSION: Sufficient level of RAR alpha is required for growth inhibition of gastric cancer cells by ATRA.

Antineoplastic Agents↗

PubMed2000

[Cancer pain and its influence on cancer patients' quality of life].

OBJECTIVE: To study cancer pain and its effect on cancer patients' quality of life. METHODS: Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) and Brief Pain Inventory (BPI) methods were used to investigate cancer pain, its effect on patients' quality of life and management in 200 cancer inpatients. RESULTS: The incidence of cancer pain was 69%, including 21.5% with mild pain, 19% with moderate pain and 28.5% with severe pain. Moderate and severe pain occurred more frequently in patients with cancer of the digestive tract. No correlation was found between pain and stage of the disease, but was closely associated with bone metastasis. Regardless of its severity, cancer pain seriously affected patients general activity, mood, walking ability, normal work and sleep. With the seriousness of pain, the patients were more affected. However, there was no obvious difference between moderate and severe pain in terms of their effect on the patients' joy of life and relations with people. The effect of moderate pain on patients' mentality appeared earlier than did severe pain. Among patients with cancer pain, 41.3% of them did not receive proper treatment. Only 52.1% of patients with severe pain were given strong opioids, which is far from the anti-pain standard set forth by the WHO. CONCLUSION: Cancer pain is one of the most important factors which affect cancer patients' quality of life. For adequate control of cancer pain, there is still a long way to go to achieve WHO's goal.

Adult↗

PubMed2000

[Localization of endothelin-1 in biopsies from oral submucous fibrosis: immunoelectron microscopic study].

OBJECTIVE: To determine the endothelin-1 (ET-1) immunoreactivity in biopsies from human oral submucous fibrosis (OSF) and to investigate the relation between ET-1 and OSF. METHODS: The localization of ET-1 in biopsies from OSF was observed with immunoelectron microscopic techniques. RESULTS: High-density deposits existed predominantly in the cytoplasm of epithelial cells, fibroblasts and endothelial cells, but not found in the biopsies of normal controls. In the biopsies of OSF, high-density granules were lined on the cell membrane, possibly on the rough endoplasmic reticulum and the mitochondria of the epithelial cells and of the fibroblasts. But a few granules were seen in the cytoplasm of the endothelial cells of microvesseles. CONCLUSION: ET-1 is one of the pathogenetic factors of OSF.

Adult↗

PubMed2000

[Effect of longshoudan on serum tumor necrosis factor and circulating endothelial cell levels in acute cerebral infarction patients].

OBJECTIVE: To investigate the effect of Longshoudan (LSD) on the serum tumor necrosis factor (TNF) and circulating endothelial cell (CEC) levels in acute cerebral infarction (ACI) patients, and the mechanism of LSD in treating ACI. METHODS: The levels of serum TNF-alpha and CEC in 40 ACI patients before and after LSD oral administration were measured by radioimmunoassay, and compared with 20 routinely treated ACI patients, and 20 healthy subjects as control group. RESULTS: (1) The levels of serum TNF-alpha and CEC in ACI patients were significantly higher than those in the control group, there was significant correlation between the increased extent and infarction size, the larger the size, the higher the levels of serum TNF-alpha and CEC; (2) In ACI patients, the serum TNF-alpha level was positively correlated with CEC level (r = 0.68, P < 0.01); (3) The serum TNF-alpha and CEC level of all ACI patients after 4 weeks were reduced, and LSD treated group was significantly lower than that of routinely treated group (P < 0.01). CONCLUSION: LSD could protect cerebrovascular endothelial cells and ischemic neurons through lowering the increased levels of serum TNF-alpha and CEC in ACI patients, and alleviate the damage of cerebrovascular endothelial cells.

Adult↗

PubMed2000

[The expression of interleukin-6 mRNA and autosecretion in human leukemic cells].

OBJECTIVE: To make a comprehensive and systematic study on the constructive expression of IL-6 mRNA and IL-6 autosecretion in human leukemic cells and discuss the effect of IL-6 autosecretion on the specific binding of IL-6-PE40 fusion protein to targeted leukemic cells. METHODS: Semi-quantitative RT-PCR, sequencing and ELISA were used to detect the constructive expression of IL-6 mRNA and autosecretion level of IL-6 protein in human leukemic cell lines, such as U937, HL60, KG1, TF1, K562, HuT28, CEM and Raji. RESULTS: The relative expression level of IL-6 mRNA in myelocytic, monocytic and erythrocytic leukemic cell lines including HL60, U937, KG1 and TF1 and lymphoblastic leukemic cell lines such as CEM, HuT28 and Raji is very weak, ranging from 0.03 to 0.07. However, K562, an chronic myelocytic leukemic cell line, had the highest level 1.25 among the 8 leukemic cell lines and the level was also higher than that of the positive control U266 multiple myeloma cell line. Based on ELISA assay of IL-6, there were remarkable differences between the 8 leukemic cell lines, their secretion of IL-6 could be divided into 3 levels, i.e. high, moderate and low secretion type. CONCLUSION: These observations imply that the intrinsic expression and secretion of IL-6 differ obviously among different leukemic cell lines. Autocrine IL-6 may prevent IL-6-PE40 fusion protein from specific binding to targeted leukemic cells and consequently affect its specific killing toxicity.

Cell Line, Tumor↗

PubMed2000

[Transoral microsurgical treatment of craniocervical malformation].

OBJECTIVE: To discuss transoral microcervical treatment of 16 patients with craniocervical malformation. METHODS: Perioperative treatment including antibiotics, tracheotomy, intravenous nutrition was used in 16 patients. RESULTS: Eight patients had basilar impressions, 3 chronic atlantoaxial dislocation and 2 odontoid fracture, 2 lower clivus chordoma, and 1 granuloma in the ventral part of the medulla oblongata. Three patients received bone graft. Follow-up for 6 - 36 months showed that 14 patients resumed normal life but 1 died. CONCLUSIONS: Pre-craniocervical malformation can be treated by transoral approach microsurgically. Understanding microanatomy of this approach can reduce postoperative morbidity and complications. Perioperative treatment can prevent incision infection. Prevention of intraoperative CSF leakage must be emphasized.Bone graft can make craniocervical spine stable.

Adolescent↗